改同义句：He feels worried about his future.

feel worried about sth.=worry about sth.

所以这个题应该是worry about

但是是he开头并且是一般现在时

所以是worries about。

worries about

worries about

He is worried about his future

应该是这样的：
He worries about his future .
有这样一个句型：feel/be worried about sth.=worry about sth.
他们的意思都是为某事担忧。

希望可以帮你！