选词填空。

that foot the fall do try they slow both of

Galileo, lived in the city of Pisa, where there is a leaning tower about 180   1   high. From the top    2 
the tower Galileo dropped a light ball and a heavy ball exactly at   3   same time. They   4   fell at about the
same speed and hit ground together. He    5   it again and again. Every time he got the same result. At last, he
decided   6   he had found the truth about    7   objects. As we know now, heavy objects and light objects
fall at the same speed unless air holds   8   back. A feather falls   9   than a stone only because the air holds
the feather back more than it   10   the stone.
1.______ 2.______ 3.______ 4.______ 5.______
6.______ 7.______ 8.______ 9.______ 10.______

查看答案