Glass milk bottles can be used again and again, but they need __________ thoroughly, ____they?

A．to clean, needn’t

B．cleaning,don’t

C．clean, aren’t

D．cleaned, can’t

液化气铜片腐蚀测定水浴应恒温在（）。

A、25±1℃

B、40±0.5℃

C、45±0.5℃

D、50±1℃