英语改错问题

Question

Not until I open it I find it was a clock.这句话的改错，答案上给的是
Not until I open it did I find it was a clock.为什么要这样改啊？

Answer 1

Not until是倒装句句型，朋友。
如果将 "not until …"的结构放在句首，那么主句要写成倒装句。例如：
They didn't realize their fault utill we pointed it out to them .
直到我们向他们指出了他们的错误，他们才意识到。
Not until we pointed out their fault to them did they realize it .
直到我们向他们指出了他们的错误，他们才意识到。

希望对你有用啊

Answer 2

Not until 放句首，后面要倒装啊

这是倒装句的用法

Answer 3

not until 开头用倒装