John,you forgot to add _____"s"to the sord "book"here.Be careful next time,please.A)the B)a C)an D)for

John,you forgot to add _____"s"to the sord "book"here.Be careful next time,please.A)the B)a C)an D)for
John,you forgot to add _____"s"to the sord "book"here.Be careful next time,please.
A)the B)a C)an D)for

John,you forgot to add _____"s"to the sord "book"here.Be careful next time,please.A)the B)a C)an D)for
C
字母S是元音发音,所以用an
John,你这里的单词“books”后面的“s” 漏了,以后请仔细一点.

A,特指用the