我发觉他有一些不对劲。
wǒ fājué tāyǒu yīxiē búduì jìn 。
I found that something was wrong with him.
他们发觉这个问题很复杂。
tāmen fājué zhègè wèntí hěn fùzá 。
They discovered that this problem is very complex.
她在书中发觉了很多有趣的事实。
tāzài shū zhōng fājué le hěnduō yǒuqù de shìshí 。
She discovered many interesting facts in the book.