泡沫灭火机不能扑灭（）的火灾。
A.精密仪器
B.油类
C.电器
参考答案：A, C
Richard turned off the computer after he had finished __________ the email.[ ]
A. write
B. to write
C. writing
D. wrote
发现燃气泄漏的怎么处理？
