There is ( ) A.key B.a set of key C a set of keys D.keys 选哪个?为什么

选C.
谓语动词的单复数根据set来定,前面的谓语动词是单数is,所以用 a set of（一串）,一串钥匙肯定不止一片啊,所以后面用复数.
就像：There is a pair of shoes.
There are two pairs of shoes.可是前面是is后面是 keys为什么可以看这个：There is a pair of shoes. 前面的is是根据set来定，而不是keys，就像这里的is是根据pair来定我们可以说：There is a key. 有一片钥匙 There are two keys. 有两片钥匙 There is a set of keys. 有一串钥匙 There are two sets of keys. 有两串钥匙 不懂再追问》》》