到目前为止，政府尚未宣布新政策。

___As ___yet, the government has not announced a new policy.

科学家们至今仍无法解释这一奇怪的现象。

Scientists ___as ___yet have no explanation for the strange phenomenon.

关于预算问题，目前还没有明确的解决方案。

___As ___yet, there is no clear solution to the budget issue.