`-` CĐK Loại `1` : Diễn tả hành động có thật ở Hiện tại

`+` If - clause : Thì HTĐ : S + Vs / es

`+` Main - clause : Thì TLĐ : S + will + V

`-` CĐK Loại `2` : Diễn tả hành động không có thật ở Hiện tại

`+` If - clause : Thì QKĐ : S + Ved / V2

`+` Main - clause : Thì TLTQK : S + would + V

`-` CĐK Loại `3 - 2` :

`+` If - clause : Thì QKHT : S + had + VpII

`+` Main - clause : Thì TLTQK : S + would + V

`-` Unless `=` If not : Trừ phi

`1`.If I knew enough about the machine , I could mend it myself

`2`.If I had a typewriter , I could type it myself

`3`.Unless Nick has a map , he can't find the way

`4`.Unless my father gives me money , I can't go on a long holiday this year

`5`.If I had got a dictionary , I could look the word up

`6`.If they didn't live so far away , we would visit our friends very often

`7`.If Lan had a bike , she wouldn't walk to school

`8`.If we don't sell more tickets at the last minute , we'll have to cancel the show

`9`.If I buy a new hat , I'll give it to you

`\text{# TF}`