Unless expresses a negative condition.
- Unless this boy stops fooling around, he won’t learn very much.
- Unless he takes the pencils out of his nose and ears, his teacher will get mad.
Otherwise expresses a negative result.
- This boy had better stop fooling around. Otherwise, he won’t learn very much.
- He should take the pencils out of his nose and ears. Otherwise, his teacher will get mad.
Unless begins a dependent clause. This clause must be joined to an independent clause.
- The girl will hit him unless he stops teasing her.
- Unless he stops teasing her, the girl will hit him.
Otherwise begins an independent clause. It comes after a period or a semi-colon.
- He ought to stop teasing her. Otherwise, the girl will hit him.
- He should be nicer; Otherwise, he will be punished.
Practice: Look at both the grammar and the meaning to help you decide which to choose. The answers are below.
- It’s raining really hard right now. __________________ you don’t care about getting wet, you shouldn’t go out.
- Don’t text and drive. _________________, you may cause an accident.
- ____________________ it’s nice tomorrow, I won’t plan a picnic in the park.
- Don’t call your teacher by her first name ______________________ she has given you permission.
- You shouldn’t smoke. ________________________, you may have health problems later.
- ____________________ our team trains harder, we won’t win the championship.
- I’d better set two alarms. _______________________, I may not wake up.
- ____________________ you show ID, you will not be allowed to enter a bar.