词形变换：选择方框里的词的正确形式填空，每词只用一次。

discover  do  surprise  burn  hold  add  heavy  find  use  observe

 

 
1. We ________ a science experiment in class tomorrow.
2. Do you know who ________ America?
3. They will show us a ________ experiment in class.
4. I have nothing ________ to my letter.
5. Air is ________ than we think.
6. The force is strong enough ________ the water.
7. I will ask the class to make ________ and guess what will happen.
8. An Easter egg hunt is a game for ________ eggs.
9. To make a candle ________, you “light” it.
10. When the candle stops burning, it ________ up all the oxygen in the air.