`1`. It was not until midnight that I wrote an IELTS essay.

`2`. He didn't start walking until he was 1.

`3`. Not until we reached the top did we realize how far we had gone.

`4`. Until last year, I hadn't seen the ocean.

`5`. They didn't pay the bill until the water was cut off.

`6`. I did not realize that I forgot my pen until I had reached my school.

`7`. The boys didn't stop playing games until their mother came.

`8`. The letter didn't arrive until yesterday.

`9`. Until last summer, we hadn't traveled to Vietnam.

`10`. The police didn't arrest the robber until they had proof.

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`@` Not until + S + V + trợ động từ + S + V

`@` It was not until + thời gian/mệnh đề thời gian + that + S + V

`@` Thì QKHT:

`-` Khẳng định: S + had + V3/ed

`-` Phủ định: S + had not + V3/ed

`-` Nghi vấn: Had + S + V3/ed?