Passive sentences utilize the passive form of the verb.  You can derive the passive form from the dictionary form of a verb in the following ways:

(a) る-verbs: Drop the final る from the dictionary form and then add られる.　

• 食べる　→　食べられる
• 見る　　→　見られる

FYI: The passive form and the potential form of the る-verb are identical.

(b) う-verbs: Drop the final hiragana character of the dictionary form (かく→か＿) and add the character in the top row within the same column (か→かか) in the hiragana table, and then add れる (かか→かかれる).  If the dictionary form ends in hiragana う, drop う (いう→い＿), add わ (い→いわ), and then add れる (いわ→いわれる).

(c) Irregular verbs:

• 来(く)る　→　来(こ)られる
• する　→　される

FYI: The passive form and the potential form of 来(く)る are identical.

Please note that regardless of the verb types, the passive form conjugates as a る-verb.

Passive sentences in Japanese can be generally divided into two types of usage, (a) direct passive and (b) indirect passive.  The latter type of usage is also called "affective passive."

(a) Direct Passive

The direct passive in Japanese is similar to the passive in English.  In English, the direct object of the active sentence becomes the subject of the passive sentence, and the subject of the active sentence is preceded by the preposition "by" as shown below:

John’s father scolded John. (active sentence)
John was scolded by his father. (passive sentence)

In Japanese direct passive, the subject of the active sentence is preceded by the particle に.

Active sentence: Xは (or が) + Yを + V (active)

Direct passive sentence: Yは (or が) + Yによって + V (passive)

• ジョンのお父さんはジョンをしかりました。(active sentence)
  John’s father scolded John.
  
  
• ジョンはお父さんにしかられました。(direct passive sentence)
  John was scolded by his father.

Since the direct object of the active sentence becomes the subject of the direct passive, only transitive verbs can be used in direct passive sentences.  When verbs indicating creative activities such as discovery, invention, and composing, instead of に, によって often precedes the person who engages in the activity in passive sentences.

• アメリカはクリストファー・コロンバスによって 発見(はっけん)されました。
  America was discovered by Christopher Columbus.
  
  
• 電球(でんきゅう)はトーマス・エジソンによって 発明(はつめい)されました。
  The light bulb was invented by Thomas Edison.
  
  
• 「風(かぜ)と共(とも)に去(さ)りぬ」という小説(しょうせつ)はマーガレット・ミッチェルによって書かれました。
  The novel Gone with the Wind was written by Margaret Mitchell.

The passive form can be used even when the agent (i.e. the person who performed the action) is unknown.

• １９９６年にアトランタで夏のオリンピックが 行(おこな)われました。
  The Summer Olympic Games was held in Atlanta in 1996.

(b) Indirect Passive (or Affective Passive)

Indirect passive often expresses the idea that the subject of the passive sentence was negatively affected by the person who performed the action (i.e., agent). Therefore, it is also known as "adversative passive."

• 妹に日記(にっき) を読まれました。
  My younger sister read my diary (and I became angry).
  
  

• 友だちに足をふまれました。
  A friend of mine stepped on my foot (and it hurt).

It is unnatural to express these negative affect incidents using the direct passive in Japanese.  Even though it is conceptually possible to use active sentences, passive (i.e., indirect passive) sentences are overwhelmingly preferred because you (or the subject of the passive sentence) are negatively affected.

Active sentence: Agentは (or が) + Victimの Direct-Objectを + active-V

Direct passive sentence: Victimの Direct-Objectは (or が) + Agentに + passive-V (unnatural)

Indirect passive sentence: Victimは + Agentに + Direct-Objectを + passive-V

• 妹は私の 日記(にっき)を読みました。(active sentence)
• 私の日記は妹に読まれました。(direct passive sentence) (unnatural)
• 私は妹に日記を読まれました。(indirect passive sentence)

Since intransitive verbs (e.g., "The baby cried.") cannot take a direct object, they cannot be used in passive sentences in English.  However, this is not the case in Japanese.  An intransitive verb can be used in the indirect passive pattern if the subject of indirect passive sentence is negatively affected by the event or someone’s action.

• かさを持たないで出かけたので、雨にふられてしまいました。
  Since I went out without taking an umbrella, I got caught in the rain. (I was rained on.)
  
  
• となりのアパートの赤ちゃんに夜おそくなかれて、あまりよくねられませんでした。
  The next-door baby cried late at night, I wasn't able to sleep well (Darn it!).
  
  
• 田中さんに先に行かれてしまいました。
  Mr. Tanaka beat me to it.
  

When transitive-intransitive verb pairs were introduced in Lesson 20, we learned that the ～ている pattern for certain intransitive verbs can express the condition which resulted from the occurrence of an action or changed states depicted by the verb.

• まどは今、開いています。
  The window is now open.
  
  
• エアコンがついています。
  The air conditioner is on.

Under ordinary circumstances, these sentences do not indicate the window or air conditioner is in the process of opening or turned on.  Instead, they indicate the current condition or state of the window or air conditioner.  That is, the window is open, or the air conditioner is on.

In this lesson, we will learn that transitive verbs can be used to depict the similar thing when their て-form is followed by ある.

• まどは今、開けてあります。
  (Someone opened the window and) it is still open now.
  
• エアコンがつけてあります。
  (Someone turned on the air conditioner and) it is still on now.
  

Although both the /transitive Vて + ある/ pattern and the /intransitive Vて + いる/ pattern depict the current condition or state of an object X, there is a difference in connotation.  The ～てある pattern implies that someone intentionally caused the change and kept it that way. In contrast, whether such a change has been brought about on purpose is unknown in the ～ている structure.

Please note that the ～てある pattern is used to depict the current condition of X, not the person who brought about the condition, the particle which follows X is usually が or は rather than を.  Compare the following sentences.

• ホテルを予約しておきました。
  I made a hotel reservation (for some future purposes).
  
  
• ホテルが (or は) 予約してあります。
  (Someone made a hotel reservation and) it is still valid.

The former sentence, ホテルを予約しておきました, describes what the speaker did whereas the latter, ホテルが (or は) 予約してあります, is about the hotel and it depicts the current state regarding the reservation.

The /V1ている間に + V2/ pattern expresses that the action (or change of state) indicated by V2 occurs sometime during the period in which the activity V1 is occurring (or the resultant state exists). 

• 私はルームメートが買い物に行っている間にアパートをそうじしました。
  I cleaned the apartment while my roommate went shopping.
  
  
• ねている間にじしんがあったそうです。
  I hear that there was an earthquake while I was sleeping.

The /V1ている間 + V2 (て-form)いる/ pattern indicates that the activity (or resultant state) V2 continues throughout the period in which the activity V1 is occurring (or the resultant state exists).

• 私はルームメートがテレビを見ている間、ずっと本を読んでいました。
  I was reading a book while my roommate was watching TV.
  
  
• 両親が出かけている間、ずっとねていました。
  I was sleeping while my parents were out.

Instead of Vている, the existence verb V and nouns indicating certain time period or activity/event may be used before 間 or 間に.

• ニューヨークにいる間にミュージカルを見に行きたいと思っています。
  I want to go see a musical while I’m in New York.
  
  
• 留守(るす)の間に山下さんから電話があったそうです。
  I heard that there was a phone call from Mr./Ms. Yamashita while I was out.
  
  
• アメリカにいる間、いつも英語で話していました。
  I was always speaking in English while I was in the U.S.
  
  
• 夏休みの間、毎日アルバイトをしていました。
  I was working part-time every day throughout the summer holidays.

In Lesson 20, we learned that /～ながら…/ can be used to express the simultaneous occurrence of two actions.  Although both /～間 (に) …/ and /～ながら…/ describe the situation expressed by "While ～, …" in English, there is a significant difference between the two.

First of all, simultaneous actions of both clauses in /V1ながらV2/ must be done by the same person.  In contrast, the simultaneous actions in /V1間(に)V2/ can be done by different persons.  Secondly, when /～ながら…/ is used, the person who performs the two actions has to be actively engaged in both actions.  When /～間 (に) …/ is used for two actions performed by the same person, s/he is not actively engaged in the action depicted in the clause preceding 間 (に).

• 私はよく音楽を聞きながら勉強します。
  I often study while listening to music.
  
  
• 私は田中さんがまんがを読んでいる間に日本語の宿題をしました。
  I did my Japanese language homework while Mr./Ms. Tanaka was reading a comic book.
  
  
• 私はミラーさんが宿題をしている間、ずっと本を読んでいました。
  I was reading a book while Mr./Ms. Miller was doing his/her homework.
  
  
• 私はせんたくをしている間に部屋をそうじしました。
  I cleaned my room while doing laundry.
  
  
• 私は手をあらいながら部屋をそうじしました。[Unacceptable]
  (not possible to wash hands and clean a room at the same time!)

In Lesson 16, we learned that Xがほしい and Xをほしがっている express the 1st or 2nd person’s desire for the object X and 3rd person’s desire for X, respectively.  We also learned in Lesson 13 that we can use /V-stem + たい/ to indicate our own desire to do something and /V-stem + たがっている/ to express the 3rd person’s desire to engage in the activity.

In this lesson, we will learn that when you want someone to do something, you can express this by using the /Vて + ほしい/.  If you wish someone not do something, you can use either /Vて + ほしくない/ or /Vない + で + ほしい/ can be used.  The /Vない + で + ほしい/ pattern expresses a stronger request compared to the expression of your preference through the /Vて + ほしくない/ pattern. The person you want to do or not to do something is followed by the particle に in these patterns.

• ルームメートに時々アパートをそうじしてほしいです。
  I want my roommate to clean our apartment from time to time.
  
  
• 友だちに夜おそく私に電話してほしくありません。
  I don’t want my friends to call me late at night.
  
  
• 私は母に私がいない時に私の部屋に入らないでほしいです。
  I want my mother not to enter my room when I’m not there.

The /Vて + ほしい/, /Vて + ほしくない/, and /Vないで + ほしい/ patterns are straightforward expression of your desire and slightly stronger than /Vて + もらいたい/, /Vて + もらいたくない/, and /Vないで + もらいたい/.

In Lesson 10, we learned to depict changes by using ～なる.  What comes before なる depends on how the state after the "change" is described.

(1) When the "after" state is described by an い-adjective, use い-Adjくなる.

• この店のコーヒーは高くなりました。
  

(2) When the "after" state is described by a な-adjective, use な-Adjになる.

• 田中さんの部屋はきれいになりました。
  

(3) When the "after" state is described by a nominal predicate, use Nになる.

• この店のコーヒーは３５０円になりました。
  

In this lesson, we will learn that when you make a change in something (X), you can describe what you do by using Xを～する.  Again, what comes before する depends on how the state after the change is described.

(1) When the "after" state is described by an い-adjective, use /Xを + い-Adjくする/.

• この店はコーヒーを高くしました。
  

(2) When the "after" state is described by a な-adjective, use /Xを + な-Adjにする/.

• 田中さんは部屋をきれいにしました。
  

(3) When the "after" state is described by a noun, use /Xを + Nにする/.

• この店のコーヒーを３５０円にしました。