Our school forbids_____ ,that is to say, we are not allowed ____ at school.

A．to smoke, to smoke

B．students’ smoking, smoking

C．students’ to smoke, smoking

D．students’ smoking, to smoke

在检修时，技师甲说，如出现时冷时热，则制冷管道可能有水份，技师乙说，储液干燥瓶进出管处温度一样，应该是堵塞了。你认为：（）

A、甲对

B、乙对

C、甲乙都对

D、甲乙都不对