19.　 He worked day and night, trying to e_______ much more money.

18.　 --Where are you going?

--Oh, there goes the bell. I am going to listen to the l_______ given by Dr. Li.

17.　 This new model is of high q________ but it is not expensive.

16.　 Why can’t you give me a p_______ answer? I really want to know “Yes” or “No”.

15.　 How can you consider that I can’t pay off the d______? I am quite able to pay back what I have borrowed from you.

14.　 M___________(蚊子) often bite people in the evening.

13.　 He drew the _________(轮廓) of a house on the paper.

12.　 It is e______ four o'clock, not one minute more nor one minute less.

11.　 The king is living in the ________(宫殿) which looks very beautiful.

10.　 The teacher stopped to drink some water and then she c______to give her lessons.