Migrations take place on land，in water, or in the air． Some animals migrate only short （）．Other migrations cover thousands of miles or kilometers．
A.
periods
B.
spans
C.
distances
D.
lengths
正确答案是C
Migrations take place on land，in water, or in the air． Some animals migrate only short （）．Other migrations cover thousands of miles or kilometers．
Migrations take place on land，in water, or in the air． Some animals migrate only short （）．Other migrations cover thousands of miles or kilometers．
A.
periods
B.
spans
C.
distances
D.
lengths
正确答案是C