在交易磋商中，有条件的接受是( )。
A．还盘的一种形式
B．接受的一种形式
C．发盘的一种形式
D．发盘的邀请
参考答案：A
We must try _____ English well because it's very useful. [ ]
A. learn
B. learned
C. learning
D. to learn
He feels lonely because he has no close friends ____.
A．to talk
B．to talk with
C．talking
D．talking with
