引信按发火原理分有压发引信、拉发音信和松发引信。
参考答案：错
— She cannot _____ her purse.
— Yes, she doesn't know _____. [ ]
A. look for, what she can do it
B. find, what to do it
C. look for, how to do
D. find, how to do it
隔离开关不能切断（）电流，其主要作用是隔离电源，具有明显的（）。
