Class begins()nine o'clock.It is over()quarter()twelve.Lunch begins()twelve.
问题描述：
Class begins()nine o'clock.It is over()quarter()twelve.Lunch begins()twelve.
They are talking()some Americans()a map()China
I am not listening()music.I am working() the computer
填适当的介词
答
Class begins (at) nine o'clock.It is over (at) quarter (to) twelve.Lunch begins (at) twelve.
They are talking (with) some Americans (about) a map (of) China.
I am not listening (to) music.I am working (on) the computer.