Not until quite recently ______ any idea of what a guided rocket is like.

单项选择题Are you going to fix the car yourself, or are you going to have it ______

单项选择题If you are attending business meetings in America, you'd better （）.

A．speak out your own ideas actively
B．keep silent and listen to others carefully
C．appear uninterested in the meetings
D．wait for your turn to speak