问题描述:
We use__or___before when we mention them for the first time.We use __when we mention them again
A.the;a;an B./;a;the C.a;/;an D.a;an;the
A.the;a;an B./;a;the C.a;/;an D.a;an;the
问题解答:
我来补答展开全文阅读