问题详情

What do scientists say about the collision of an asteroid with Earth？
A．It is very unlikely but the danger exists.
B．Such a collision might occur once every 25 years.
C．Collisions of smaller asteroids with Earth occur more often than expected.
D．It"s still too early to say whether such a collision might occur.此题为多项选择题。请帮忙给出正确答案和分析，谢谢！