单轨吊安全回路可实现（）种保护。
参考答案：5
Could you please _____ out the trash? [ ]
A. takes
B. to take
C. take
D. taking
去蜡之前通常将型盒在热冰中浸泡，浸泡时间是
A．5～10minB．10～15minC．15～20minD．25～30minE．35～40min
