Complete the sentences with the given wo

问题：

Complete the sentences with the given words in their suitable forms. (共8分)

小题1:Some parents purchase new _______________ (toy) for their kids before Christmas.

小题2:All the classmates took the difficult exam, but only _______________ (fifth) of them passed.

小题3:They were proud to say these paintings belonged to _______________ (they).

小题4:The professor made an interesting _______________(speak) at the meeting. 

小题5:Children were fond of reading _______________ (excite) stories in their free time. e

小题6:They had a(n) _______________ (happy) trip because of the bad weather.

小题7:PM2.5 is _______________ (main) caused by air pollution in some parts of the country.

小题8:The doctor is ready to _______________ (operation) on his broken leg.