机械图中的不可见轮廓线用（）表示。
A.细点画线
B.粗实线
C.虚线
D.波浪线
参考答案：C
If you don't mind a little cold, you can enjoy different winter scenes in Huangshan and save some money
on tickets and _____ due to the weather. [ ]
A. accommodation
B. occupation
C. equipment
D. furniture
手动火灾报警按钮的连接导线，应留有不小于（）mm的余量，且在其端部应有明显标志。
A.100
B.150
C.200
D.250
