2018屆高考英語Unit 2Robots復習專項教案
11.引導主語從句或置于句首時。
12.后面直接接or not時。
13.引導同位語從句，用以說明前面的名詞的內容時。
14.后緊跟不定式時。
15.引導表語從句，表示“是否”時。
四、主語從句和賓語從句有時常用it作形式主語或賓語
16.it作形式主語的常用結構：
①it＋系動詞＋名詞＋that從句
②it＋系動詞＋形容詞＋that從句
③it＋特殊動詞＋that從句
④it＋be＋過去分詞＋that從句
17.it作形式賓語的常用結構：
①主語＋謂語＋it＋從句
②主語＋謂語＋介詞＋it＋從句
③主語＋謂語＋it＋形容詞＋從句
④主語＋謂語＋it＋名詞＋從句
⑤主語＋謂語＋it＋過去分詞＋從句
專題專練
1.(•重慶卷)to improve the quality of our products, we asked for suggestions ________ had used the products.
a.whoever b.who
c.whichever d.which
答案：a
解析：考查連詞。whoever引導賓語從句，并在從句中作主語，相當于anyone who。
2.(•上海卷)when changing lanes, a driver should use his turning signal to let other drivers know ________.
a.he is entering which lane
b.which lane he is entering
c.is he entering which lane
d.which lane is he entering
答案：b
解析：考查賓語從句，從句中要用陳述句語序。
3.(•上海卷)one reason for her preference for city life is ________ she can have easy access to places like shops and restaurants.
a.that b.how
c.what d.why
答案：a
解析：考查名詞性從句。reason作主語，表語從句用that引導，不用because。
4.(•陜西卷)it never occurred to me ________ you could succeed in persuading him to change his mind.
a.which b.what
c.that d.if
答案：c
解析：考查固定句型。我從來沒有想到你能成功地說服他改變主意。it occurs to sb. that...的意思為“某人突然想到……”，其中that引導主語從句，it為形式主語，指代that從句的具體內容。
5.(•福建卷)we should respect food and think about the people who don't have ________ we have here and treat food nicely.
a.that b.which
c.what d.whether
答案：c
解析：考查名詞性從句。我們應該重視食物，想想那些得不到我們所擁有的這些的人，好好對待食物。此處考查賓語從句的引導詞，從句中缺少賓語，故選what作動詞have的賓語。
6.(•浙江卷)it is uncertain ________ side effect the medicine will bring about, although about two thousand patients have taken it.
a.that b.what
c.how d.whether
答案：b
解析：考查名詞性從句。此處是由what引導的主語從句，指代it的具體內容，it是形式主語，所以這里選b項。
7.he didn't make________clear when and where the meeting would be held.
a.this b.that
c.it d.these
答案：c
解析：本題考查引導詞it的用法。本題句意為：“他清楚地說明了會議召開的時間和地點。”c選項it在這里用作形式賓語代替后面when and where引導的賓語從句。引導詞it的這種用法不能被其它選項中的代詞所取代，故答案選c。