Scientists and experts said it was a big ________in China's space history that Chang'e-II has been smoothly sent around the moon.
A.leap |
B.chance |
C.time |
D.opportunity |
推荐套卷
Scientists and experts said it was a big ________in China's space history that Chang'e-II has been smoothly sent around the moon.
A.leap |
B.chance |
C.time |
D.opportunity |