As a noun, it means a length of time during which something happens.

作为一个名词，它的意思是发生某件事情的时间长度。

" Term" can also mean a length of time.

“期限”也可以表示时间长度。

Dys meaning wrong and metria meaning length.

Dys意思是错误 metria意思是长度。

Although this expression can mean any length of time, it usually means " a long time, " as in this example: For some time, auto makers have worked to make cars safer.

虽然这个短语可以表示任何长度的时间，但它通常表示“很长时间”，比如下面这个例句：很长一段时间以来，汽车制造商一直在努力让汽车更安全。