Students should be __________ in class.Only listening without taking part in the activities is not good for one’s study.[ ]

I think using Wechat every night is a waste of time.—Yes. In fact, there are ______ meaningful things to do.

My ______sister who works in the bank is two years______than I.

several natives advancing towards our party, and one of themcame up to us, __________ we gave some bells and glasses.

At the top of the high mountains, there is very _____ oxygen in the air.