二氟甲烷是性能优异的环保产品，它可以代替会破坏臭氧层的“氟利昂”用作致冷剂，试判断二氟甲烷的结构简式（ ）．
二氟甲烷是性能优异的环保产品，它可以代替会破坏臭氧层的“氟利昂”用作致冷剂，试判断二氟甲烷的结构简式（ ）．
用作
The pot _____ for _____ hot water.
The pot \_\_\_\__ for \_\_\_\__ hot water.
A _____ language is one which is still spoken by people in the course of their everyday lives.
A \_\_\_\__ language is one which is still spoken by people in the course of their everyday lives.
下列仪器中不能加热的是____；能直接放在火焰上加热的是____；要放在石棉网上加热的是____．①坩埚②烧杯③烧瓶④蒸发皿⑤锥形瓶⑥量筒⑦试管⑧容量瓶⑨集气瓶⑩水槽
下列仪器中不能加热的是\_\_\_\_；能直接放在火焰上加热的是\_\_\_\_；要放在石棉网上加热的是\_\_\_\_．①坩埚②烧杯③烧瓶④蒸发皿⑤锥形瓶⑥量筒⑦试管⑧容量瓶⑨集气瓶⑩水槽
I was trying to get into the _____ bus when I heard a voice from behind.
I was trying to get into the \_\_\_\__ bus when I heard a voice from behind.
