The air in big cities ______ very dirty by factories.
The air in big cities ______ very dirty by factories.
Factories and c____ make the air dirty.
More people feel there is to much dirty air in big cities.求全
The air in mountain areas is _that in big cities
Some factories is poring dirty air in the sky.这就话对么?
the air in shenyang is very dirty.let s stop____it.
in big cities,air p______is quite serious.
Cleaning woman in big cities get ____ by the hour.
The air is very dirty.对very dirty提问
the air in mountain areas is _ that in big cities.A.as fresh
cities will be very big and crowded in the future对very big a
There is more and more air __(污染)in the big cities .填什么形式