裂缝控制一般分为()个等级。
A.三
B.二
C.四
D.五
参考答案:A
I gave up the piano lessons because I have so much homework to do, but it’s _______ my own wishes.[ ]
A. in
B. on
C. for
D. against
反馈包括反馈信息、()和反馈接收者三个要素。