$\text{Form:}$

`+)` If + S + V(-s/es) + adv/O, S + will + V(inf) + adv/O

`+)` Unless `=` If not

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`18.`

`->` Unless he submits the project, he won't graduate.

`19.`

`->` Unless you agree to help me with his job, I will tell her the truth.

`20.`

`->` If you don't promise to return back, I won't lend you.

`21.`

`->` Unless you like this one, I'll bring you another.

`18.` Unless he submits the project, he won't graduate.

`19.` Unless you agree to help me with this job, I will tell her the truth.

`-` Vì 'Unless = If not' nên ta cũng có thể đổi khẳng định `⇔` phủ định cho mệnh đề chính

`20.` If you don't promise to return back , I won't lend you.

`21.` Unless you like this one, I'll bring you another.

`-----------`

`-` Unless = If not: Trừ khi ...

`-` CĐK loại 1: If + S + V(s/es), S + will/can/may + V-inf

`->` Diễn tả một sự việc có thể xảy ra trong hiện tại hoặc tương lai