人工整平堤顶时，可铲高垫洼或另取黏性土填垫低洼处，整平后用（）夯实。
A.拖拉机
B.木人夯
C.平碾
D.振动碾
参考答案：B
The person in ________ charge of the program was at ________ complete loss when the incident happened.
A．不填；不填
B．
C．the; 不填
D．the; a
请说出两辆车合并成一辆车的操作流程。
