1、必修三unit 3 Diverse Cultures語法精講省略If、狀語從句、動詞不定式省略句必修三unit 3 Diverse Culturesif省略結構if省略結構if省略結構在if引導的虛擬語氣中：如果從句中含有助動詞were，had(done)，should省去if，把were，had，should提到從句句首if省略結構在if引導的虛擬語氣中：典例分析1. If John were here，he would know what to do.Were John here，he would know what to do.要是約翰在這兒，他會知道怎么做。同義句轉化(1)典例分析1.

2、 If John were here，he wo典例分析2. If anything had happened，he would have let her know.Had anything happened，he would have let her know.要是發生了什么事，他會讓她知道的。同義句轉化(2)典例分析2. If anything had happene典例分析3. If it should rain tomorrow, I would stay at home.Should it rain tomorrow，I would stay at home.若是明天下雨，我就待在家

3、里。同義句轉化(3)典例分析3. If it should rain tomor_(shall) he come, the problem would be settled.解析：通過would be settled可判斷此句為虛擬語氣，從句中省略if，提前should。語法填空。考點追擊Should_(shall) he come, the 狀語從句中的省略狀語從句中的省略可以省去從句的主語和be動詞：1.當從句的主語和主句的主語一致(或者從句的主語為it)；2.從句謂語中包含be動詞。狀語從句中的省略可以省去從句的主語和be動詞：狀語從句中的省略典例分析1. Dontspeakuntil（

4、youare ）spokento.2. While（Iwas）walkingaloneinthestreet,Iheardmynamecalled.（1）當從句的主語和主句的主語一致，且從句謂語中包含be動詞，省去從句的主語和be動詞。被保留部分常為現在分詞、過去分詞、不定式、形容詞典例分析1. Dontspeakuntil（youa典例分析1.IllbuyaTVsetif （itis）necessary.2.Once (itis) begun，itmustbedonewell（2）當從句的主語為it且從句謂語中包含be動詞時，省去it和be動詞。典例分析1.IllbuyaTVsetif （i

5、t常見短語if so 如果這樣的話 if not 若非如此if ever 如果曾經有的話 if necessary 如果有必要的話if possible 如果可能的話 if any 如果有的話狀語從句中的省略（3）例：1. If necessary, ring me. 2. If possible, let me know beforehand.常見短語if so 如果這樣的話 When _ (expose) to danger and conflict, men tend to increase blood pressure, feeling nervous or anxious.解析：狀語

6、從句中符合省略的條件（主語一致，有be動詞），故省略they are.語法填空。考點追擊exposedWhen _ (expose) to danger不定式的省略不定式的省略用法1常在be afraid/glad/happy, expect, forget, hope, intend, like, love, mean, prefer, refuse, seem, try, want, wish等的后面。 1. 單獨使用不定式符號 用來代替動詞不定式后面被省略的動詞用法1常在be afraid/glad/happy, exp典例1.I asked him to see a film, but

7、 he didnt want to(see a film).2. Will you join in the game?-Id be glad to (join in the game).3.-Are you a sailor?-No, but I used to be.如果不定式中含有be、have、have been，通常保留be、have、have been1. 單獨使用不定式符號 用來代替動詞不定式后面被省略的動詞典例1.I asked him to see a film,用法2（1）當主語部分含有動詞do的某種形式時，做表語的動詞不定式可省略to。例：The only thing yo

8、u have to do is （to）press the button.2.省略不定式符號to的情況（1）用法2（1）當主語部分含有動詞do的某種形式時，做表語的動詞用法3（2）不定式作介詞but、except的賓語，前面有實義動詞do的某種形式時，不定式常省略to。例：Brian had nothing to do but （to）play computer games this afternoon.2.省略不定式符號to的情況（2）用法3（2）不定式作介詞but、except的賓語，前面有實用法4（3）當兩個或兩個以上的不定式并列時，后面的不定式符號to常省略，但表示對比關系時不省略。例

9、：Im really puzzled what to think of and （to）express. It is easier to make a plan than to carry it out.3.省略不定式符號to的情況（3）用法4（3）當兩個或兩個以上的不定式并列時，后面的不定式符號用法5（4）在see、watch、hear、feel、observe、look at等感官動詞及使役動詞let、make、have后作賓語補足語的不定式不加to，但被動句中要加上to。例：I saw him enter the building. He is often seen to play basketball on the playground.4.省略不定式符號to的情況（4）用法5（4）在see、watch、hear、feel、obsThe city now is muc