__________ in watching the car passing by that he didn't notice his friends.
He waited until it was dark ____ nobody could see him clearly.
Now there are many _____ in our company.
We should think of ways to stop the waste from the factory _____ our living environment.
In my opinion, all Mr. White ___ good to his students in his class at present. He is very strict in their study.
___ nice, the food was sold out soon.