问题

Lessons can be learned to face the future, ________ history cannot be changed.

A:though
B:as
C:sinceDunless
D:unless

正确答案是：

同类题型

I hope we can have ________ homework to do at weekends.—-That’s what I think. Then we can have ________ free time for my hobbies.

Expertsthink that ____recently discovered painting may be _____ Picasso

Have you ever to Xi’an, Betty —Yes. I there last month.

下列各句没有语病的一句是（）

The wireless video camera is ________to send its video signal to a nearby base station，allowing it to be viewed on a computer or a television