问题

Why does the lake smellterrible—Because large quantities of water ______.

A:have polluted
B:is beingpolluted
C:has beenpolluted
D:have beenpolluted

正确答案是：

同类题型

You can’t have lost the keys.___ all yourpockets again.

He _____ have fallen asleep last night because hedidn’t hear the phone call.

.—Shall we ______ for half an hour and have a tea? —I can’t agree with any more.

What she said made me _____ very angry.

he is very young, he can do many things.