I think /guess people will live up to 200 years old in 100 years.
or
In my opinion,in 100 years, people will live up to 200 years old
祝你开心如意!O(∩_∩)O~~
is going to live
希望能帮到你。
be going to =will.将要
I think in 100 years people will live to be 200 years old.
I think after one hundred years,people will live to be two hundred years old.
In my opinion, people will live 200 years in the next century