Twelve were boys.

8.不定式/動名詞/從句作主語時的主謂一致。

①單個不定式或動名詞作主語，謂語用單數(shù)。兩個或兩個以上互不關(guān)聯(lián)的事，謂語用復(fù)數(shù)。兩個或兩個以上密切關(guān)聯(lián)為一件事，謂語用單數(shù)。如，

●To die for the people is a worthy death.

●Looking after the children is my full time job.

●When and where to hold the meeting is unknown.

Playing basketball and swimming are his favorite sports.打籃球和游泳是他最愛的運動。

Going to bed early and getting up early is a good habit.早睡早起好習(xí)慣。

②單個從句作主語時，謂語用單數(shù)。兩個或兩個以上，謂語用復(fù)數(shù)。由what引導(dǎo)的主語從句，根據(jù)整個謂語部分的意思確定謂語首詞的數(shù)，因為，無法從what從句本身看出來單/復(fù)數(shù)what本身表示單數(shù)或復(fù)數(shù)意義都可以。

●Which of them was right was quite clear to us.

●When men first made use of electricity is not exactly known.

What we need is more time.（根據(jù)表語time，謂語首詞用單數(shù)）

What we need are doctors. （根據(jù)表語doctors，謂語首詞用復(fù)數(shù)）

What he says and does do not agree.他的言行不一致。（單數(shù)）

What he says and does does not concern me.他的言行與我無關(guān)。（復(fù)數(shù)）

※鏈接：其它章節(jié)中講到的主謂一致。1.總稱名詞和專有名詞作主語時的主謂一致，參看第三章第三節(jié)冠詞在總稱名詞/專有名詞前的用法。2.不定代詞(+of)作主語時的主謂一致，參看第四章第四節(jié)不定代詞的用法總表。3.“the+形容詞”作主語時的主謂一致，參看第八章第二節(jié)“the+形容詞”的用法。4.定語從句的引導(dǎo)詞作主語時的主謂一致，參看第十一章第五節(jié).what/which/that引導(dǎo)的定語從句。