小题1: Collecting stamps is one of my __________（爱好）.

小题2:It’s not __________（礼貌的）to talk with your mouth full.

小题3: I think the telephone was __________（发明）in 1876.

小题4: China is getting richer and stronger in the new __________（世纪）.

小题5: We’ll be able to finish the project _________（容易的）.

产品气压缩机是一个（）离心式压缩机。