问题

You promised your friend a letter; youought to ______ days ago.

A:write
B:be writing
C:have written
D:be written

正确答案是：

同类题型

____________ town it is !—Yes .Great changes have taken place here since we began to build a civilized（文明的）city .

Only in this way ______ progress in your Japanese.

The present situation is very complex,so I think it will take me some time to_______ its reality. [ ]

I will go to Dalian with my parents next month. — .

____ has been reported _____ sales ofbeef in China will increase