`3`. If you aren't careful, you may have an accident.

`4`. If you have a trouble, phone your parents.

`5`. If she doesn't whisper, everyone knows what she is saying.

`6`. If you stay here, you will feel save.

`7`. If you don't pay electricity bill today, your electricity will be cut off.

`8`. If you don't stop smoking, your cough may be worse.

`9`. If we don't use less fossil fuel, they will be run out soon.

`10`. If it doesn't stop raining today, we may be faced with a serious flood.

`11`. If you do morning exercises regularly, your body will be fitter.

`12`. If we don't renewable energy, we will have nothing for the future generation.

`13`. If we don't reduce the use of non-renewable energy, the climate will change.

`14`. If you lock all the doors, no one can break into your house.

`15`. If we don't continue hunting polar bears, they will become extinct in near future.

`--------`

* Câu điều kiện loại `1->` Diễn tả giả thiết có thể xảy ra ở hiện tại hoặc tương lai.

`*` If clause: Hiện tại đơn

`*` Main clause: S + will/can/may/... + (not) + V bare + ...

* If + S + V (hiện tại đơn), V + O.

- Unless = If ... not : Nếu không

- Tình huống với "and" không cần đổi thể ; tình huống với "or" cần đổi thể.