发动机启动后松开（），车辆运行。
参考答案：制动按钮
（）催化剂用来生产宽分子量分布的聚乙烯产品。
A、UCAT-J
B、UCAT-A
C、UCAT-B
D、UCAT-G
The parents suggested ___ in the hotel room but their kids were anxious to camp out
during the trip .
A．sleep
B．to sleep
C．sleeping
D．having slept
