as yet

到目前为止, 迄今

例句与用法：

The side-effects of the drug are as yet unknown (toscientists).

这种药的副作用(科学家)尚未发现。

As yet we haven't heard from him.

我们到现在还没有收到他的信。

We are as yet unable to say when the train will arrive.

我们还说不上火车什么时候到达。

We should be responsible for the generation as yet unborn.

我们应该对下一代负责。

详细释义：

迄今为止

We have received no answer from him as yet.

我们至今还没得到他的答复。