awhile ago Her mother died a while ago. 她母亲不久前去世了。

for a while We haven’ t seen Barry for a while. 我们有一段时间没看见巴里了。

quite a while (=afairly long period) I’ ve been waiting here quite a while. 相当长的一段时间

ashort/little while Couldn’ t you stay just a little while longer? 难道你不能再多呆一会儿吗？

She pretended to be asleep, but all the while she was watching him. 她假装睡着了，其实整段时间她一直在观察他。