问题
选择题
.________ gas leaks and similar accidents should occur, some responsible persons should regularly inspect all the laboratories.
A．Unless
B．In case
C．Provided
D．Until
答案
答案：B
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.________ gas leaks and similar accidents should occur, some responsible persons should regularly inspect all the laboratories.
A．Unless
B．In case
C．Provided
D．Until
答案：B