这道题怎么做：It's certainly hard

It's certainly not for me.这里面certainly不是副词吗?怎么能修饰be动词呢? "It's hard to die"怎么解释? it's certainly not for me! it's hard to It‘s certainly not for me!能否写成It is not certainly for me!为什么 英语语法it's certainly that 有这种用法吗? It's certainly not for me 意思应该是? “It's hard to die. but It's hard to It's So Hard 歌词 oh,it's too hard It's (rain) hard outside.