Carbon dioxide, which makes a _____ between us and the sun, prevents heat from getting out of the atmosphere easily, so the earth is becoming warmer.
A.difference |
B.comparison |
C.connection |
D.barrier |
推荐套卷
Carbon dioxide, which makes a _____ between us and the sun, prevents heat from getting out of the atmosphere easily, so the earth is becoming warmer.
A.difference |
B.comparison |
C.connection |
D.barrier |