地震来了，使人感到上下颠动的是（）。
A、横波
B、纵波
C、面波
D、体波
参考答案：B
Every year a flood of farmers arrive in Shenzhen for the money-making jobs they _____ before leaving their
hometowns. [ ]
A. promised
B. were promised
C. have promised
D. have been promised
