Phrase
as yet
adverb
至今；迄今
up to the present
- 1.
Up to the present.
到目前为止。
到目前为止。；至今仍
In use
As yet, no decision has been made.
The cause of the accident is as yet unknown.
We have as yet received no response.
as yet + negative clause
常用于否定句，强调至今仍未发生。
The results are not available as yet.
结果至今仍不可用。
as yet + interrogative clause
在疑问句中类似‘已经’，但更正式。
Has the report been completed as yet?
报告至今已完成了吗？
as yet + present perfect
常与现在完成时连用。
The project has not started as yet.
项目至今尚未开始。
Common mistakes
I finished my homework as yet.I haven't finished my homework as yet.
as yet 通常用于否定句或疑问句，表示‘至今仍未’，不能用于肯定句。改为否定句并用现在完成时。
I didn't finish my homework as yet.I haven't finished my homework as yet.
as yet 与现在完成时搭配，表示从过去持续到现在的状态，而一般过去时只表示过去动作，不延续到现在。需改为现在完成时的否定形式。
Connections
Learner notes
Grammar Note
正式用语，多用于否定句或否定语境。
Dictionary facts from ECDICT, WIKTIONARY.