推进车辆运行前要试拉的原因？
参考答案：
为了检查车钩的连挂状态，以防车辆没有连挂好，在推进中发生分离或车辆溜逸。
Read and choose.（读句子，选择恰当的答语）
1. What do you usually do on the weekend? [ ]
A. I often play football.
B. I played football.
2. What do you do? [ ]
A. I usually go shopping.
B. I am a teacher.
3. When do you get up?[ ]
A. At 6:00.
B. Sure.
4. What do you do on the weekend? [ ]
A. It's great!
B. Sometimes I climb mountains.
城市规划的实施是一个综合性的概念，它是指( )的行为。
A．城市规划行政主管部门
B．城市人民政府
C．政府、公民、法人、社会团体
D．政府、规划行政主管部门
