我必须说，ULD已经产生了一段时间了，但是最近进行了一些精炼。

I should say, uld has been around for quite a while but there have been some recent refinements.

youdao

我必须说，ULD已经产生了一段时间了，但是最近进行了一些精炼。

I should say, uld has been around for quite a while but there have been some recent refinements.

youdao