a nest is to a bird __a house it to a man. A,where B, how C, what D,when 为什么要选D
问题描述：
a nest is to a bird __a house it to a man. A,where B, how C, what D,when 为什么要选D
答
因为where是指什么地方，how是指怎么样，what是指什么，而when是当.........的时候。a nest is to a bird __a house it to a man这句话要用介词，所以用介词when
答
a nest is to a bird when a house it to a man.那个时候，巢之于鸟如同屋之于人。（强调时间）
答
意思是
鸟巢对于鸟来说就好像房子对于人.
但楼上两位都填错了,应该是what
a nest is to a bird what a house is to a man
同类例句
Honey is to a bee what milk is to a cow