涉及倒裝的主語一致考題

Mr Smith has bought a little house in the country, around _________ some green trees.

A. which is               B. it is                      C. which are            D. them are

【分析】此題容易誤選A或B，將A、B中的 which 和 it 誤認為是其后句子的主語。其實，此題的最佳答案為C，around which are some green trees 是一個由“介詞+which”引出的非限制性定語從句，而在該從句中，主語是 some green trees，around which 是表語，所以句子謂語應用are，而不是 is。請看類例：

Among these people was a foreigner from Europe. 他們當中有一個來自歐洲的老外。(句子主語是 a foreigner，among these people 是表語，所以謂語動詞用單數 was)

On the top of the tree were some birds. 樹頂上有一些鳥。(句子主語為 some birds，on the top of the tree 是表語，所以謂語動詞用復數 were)

The police found a large box under his bed, in which were some sex books. 警察在他的床底下找到一只大箱子，里面裝的是一些黃色書籍。(in which were some sex books 為非限制性定語從句，在該從句中，in which 是表語，some sex books 是主語，所以謂語動詞用復數were)