I had a nagging feeling that I had forgotten something.

有某种不安的感觉，好像忘了西似的。

I had a queer sensation as if a worm was creeping down my spine.

有一种可疑的感觉, 好象有个虫子在顺着的脊梁往下爬似的。

He felt a species of uneasiness.

他有一种不安的感觉。