In first conditional sentences, we use a simple present tense in the if-clause and will + infinitive in the main clause. There are several alternate forms, too. Here is an overview.
Sometimes we use going to instead of will in the main clause. This is done to emphasize a certain result.
Study the sentences given below.
- If she works hard, she is going to win. (= If she works hard, she will win.)
- If you drink too much alcohol, you are going to land in hospital with liver problems.
- If he drives too fast, he is going to have an accident soon.
Going to can also be used in the if-clause. In this case it means ‘intend’.
- If she is going to skip her classes, she will certainly fail her exams. (= If she intends to skip her classes, she will certainly fail her exams.)
The present perfect tense is sometimes used in the if-clause to put the focus on the completion of an action.
- We will go grab something to eat if you have finished your work.
- We will wait for her if she has not arrived yet.
Should can be used in the if-clause to suggest that something is unlikely.
- If he should be late, we will have to start without him. (He is unlikely to be late but if HE IS we will have to start without him.)
- If Peter should arrive in time, we will take him along to the party.
Note that would is not possible in this case. For example, we can’t say: If he would arrive on time, we will take him along.
- If I should run into Alice, I will give her the books.
Note that the first conditional forms with should indicate greater probability than the second conditional forms.