4.　　 Which do you prefer to use to wash your hair, soap or s__________?

3.　　 Do you know why l________ comes into sight before t_____ comes into our ears?

2.　　 If you are feeling cold, you needn’t take off your g______ to protect your hands.

1.　　 Students must c_________(做) e_______ when they study physics or chemistry.

20.　 He went into his room on the second floor through the window with a l______ because he had left his keys in his room.

Unit 16

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.