I-[not think]he is smart enough-[work]out the maths problems.

I-[not think]he is smart enough-[work]out the maths problems.
I-[not think]he is smart enough-[work]out the maths problems.

I-[not think]he is smart enough-[work]out the maths problems.
I don't think he is smart enough to work out the maths problems.

don't think, to work

don't think
to work
比较简单的，一定正确的哦~

I don't think he is smart enough to work out the maths problems.
我认为他没那么聪明可以做出那道数学题