419.You should look ____ into the matter to get more information about it.

A.farther

B.far

C.farthest

D.further

420.We could hardly believe what she says because she is _____ changing her mind.

A.regularly

B.steadily

C.suddenly

D.constantly

419.答案是D;

look further into the matter更深入地调查此事。

420.答案是D;

regularly 定期地，有规律地；steadily 稳定地；suddenly 突然地;constantly 经常，不断

地。