八年級英語上冊Units7-9知識歸納
a.joined b.took part in c.became d.were
解析：本題考查join的用法，join為“參加某一個組織”；take part in為“參加某一活動”。故選a。
3、because, because of
because是連詞，其后接句子；because of是復合介詞，其后接名詞、代詞、動名詞、what從句等。如：
i didn’t buy it because it was too expensive. 我沒有買是因為它太貴了。
he is here because of you （that）. 他為你（那事）而來這里。
he lost his job because of his age. 由于年齡關系他失去了工作。
we said nothing about it， because of his wife’s being there. 因為他妻子在那兒，我們對此只字未提。
he knew she was crying because of what he had said. 他知道她哭是因為他說的話。
注意：because of 之后可接 what 從句，但不能接 that 從句或沒有引導詞的句子。如：
他因生病沒有來。
誤：he didn’t come because of he was ill.
誤：he didn’t come because of that he was ill.
正：he didn’t come because he was ill.
正：he didn’t come because of his illness.
比較以下同義句：
他離開了這家公司，是因為老板在會上講的話。
正：he left the company because of what the boss said at the meeting.
正：he left the company because of the thing that the boss said at the meeting.
我不能因為有個家就停止斗爭。
正：i can’t stop fighting because i have a family.
正：i can’t stop fighting because of having a family.
二、被動語態
被動語態考點例析
a、考查要點：
主要考查一般現在時，一般過去時以及一般現在時帶有情態動詞的被動語態的用法。例如：
1. today chinese _____by more and more people around the world.
a. was spoken b. is spoken c. spoke d. speak
（北京市大綱卷）
2. -what should we do first if we want to develop our village？
-a lot of new roads _____，i think.
a. have to build b. must build c. have built d. must be built
（湖北黃岡）
（key：1. b 2. d）
簡析：被動語態的句子是由助動詞be＋動詞的過去分詞這一形式構成的。過去分詞永遠不變，所有的變化即人稱、數、時態的變化，都體現在助動詞be的變化上。
b、特殊情況：
（一）在沒有必要指出動作的執行者時，by＋動作的執行者可以省略。
1. i won’t leave my office until my work .
a. finish b. will finish c. are finished d. is finished
（江蘇南通）
簡析：d.動作的執行者很明確，可以省略。
（二）不知道動作的執行者是誰，使用被動語態比較適宜。
2. dad， the phone is ringing. i guess either you or mum_____on the phone.
a. is wanted b. are wanted c. wants d. want
（江蘇宿遷）
簡析：a.不清楚動作的執行者，用被動語態。
（三）用于被動語態的短語動詞不可丟掉動詞后面的介詞或副詞。
3. students can’t take magazines out of the reading-room. （改為被動語態）
magazines can’t _____ the reading-room by students.