I really hate it when it is always rain.这两个“it”起什么作用?

I really hate it when it is always rain.这两个“it”起什么作用? I hate it when it is rains i hate it when it rains.it is much(w)than it was yesterday It always ___(rain)when I am not learning. I hate it tthat 从句与I hate it when从句有什么区别? I hate it when people always tell me what I shoud do. When it ___ (rain) 请英语大师指点,这句话中when到底是什么成分?什么作用?It is almost always due to some really++when+is+it++open是什么意思 But it rain again when I is playing basketball ,rain 是可持续动词, It is a true story .Really .When and where [ ]it[ ] When I arrived,it was early morning and it __(rain)横线上填什么?谢谢