20/5t桥式起重机主钩下降控制过程中,空载慢速下降,可以利用制动“2”挡配合强力下降()挡交替操纵实线控制。
A、“1”
B、“3”
C、“4”
D、“5”
参考答案:B
we have teachers this year than last year. [ ]
A. many
B. much
C. more
D. the more
行使不安抗辩权时有哪些限制?