用所给动词的适当形式填空
I hope scientist________(find)a cure of cancer.
By the middle of this century, more people________(live)in cities than in the country.
Ten years from now, people________(wear)smart clothes.
No one________ever________(live)on Mars.
Humans________(live)on another planet five billion years from now.
A Chinese astronaut________(reach)Mars by 2050.