One word that is difficult for Japanese students to use is unless. Let's take a look at how we can use unless in our conversations.
We use unless to show a condition that stops something from happening. For example:
◆I will go jogging tomorrow unless it rains. = Rain will stop me from going jogging.
◆Unless he studies hard, he can't pass the test. = Not studying hard will stop him from passing the test.
Keep in mind that the verb you use with unless is usually in the present tense. For example:
◆I'll be there by 12 noon unless the train is delayed.
◆× I'll be there by 12 noon unless the train will be delayed.
Be careful — it may seem like unless is the same as "if…not," but actually they are slightly different. While they sometimes mean the same thing, there are also examples where the meaning would be different. For example: