已知试件拉断后标距部分长度L1=300mm,原标距长度L0=200mm,则该试件伸长率为( )。
A.150%
B.50%
C.66.7%
D.33.3%
参考答案:B
The man in black has two children, one of whom _______ in a foreign country.
A.brought back
B.was brought back
C.was brought up
D.brought up
在清管作业中,由于管线的内部污物太多,清管器在管内()而形成堵塞。
A.缓慢运行
B.无法运行
C.中速运行
D.强制运行