1.除了happened改用一般现在时happens之外,而且必须去掉it.
即正确写法为：Whatever happens,life will always go on.
不管发生什么,生活总（还是）要继续（下去的）.
2.
Whatever happens,life will always go on.
= No matter what happens,life will always go on.
1）让步状语从句用一般现在时,而主句用一般将来时,即状语从句中时态的“主将从现”原则；
2）whatever = no matter what,而what就做happens的主语,所以it是多余的.