1.一You have dropped_______“s”in the word“necessary”.一Oh,______letter“s”is doubled.

问题描述:

1.一You have dropped_______“s”in the word“necessary”.一Oh,______letter“s”is doubled.

an:s是元音开头的,
这里是泛指,因为后文里意思是只丢了一个,用the就是全丢了.
the:前文已经提到过那个了,就是特指