fall over the moon意思是?

问题描述:

fall over the moon意思是?
she is vegetarian .she will ____if you mention eating meat in front of her .
A.fall over the moon B.be down in the dumps
C.get hot under the collar D.laugh her head off

倒过来的月亮应该不是这个意思!!.......那么.....翻倒的月亮?这是一个选择题中的短语!应该是口语上的一些意思把???和月亮应该没多大关系!好吧..