Now that you're studying English at a high level, you need to be able to talk about the language itself.
One of the biggest areas of confusion for students is the difference between the past tense and the present perfect
The past tense is indicated by use of the past tense marker, represented here by V(d)
Here are some examples of regular verbs and their past tense forms
So as you can see, for regular verbs the past tense forms is indicated by the addition of an -ed at the end of the verb.
However some of the most common verbs in English are irregular, so it is important to learn them.
Here are some examples
Many people think that the past tense form only indicates past time.
However, that is only one of the possible meanings
The past tense form is also used to express something that is unlikely or imaginary,from the speaker's point of view.
Here is an example:"He wishes he had a car"
The fact is that he doesn't have a car, so the use of had indicates that it isn't real: it's imaginary
If he had a car, he could drive us to school.
Again he doesn't have a car so he can't drive us to school
This condition expresses something that isn't a fact
It's a counter-factual condition, which means it goes against what we know or believes
Both sentences are correct, but there is a difference in meaning
(If she waits another week, she can save money
if she waited another week, she could save money because there's going to be a sale
In the top sentence, the condition that she waits is more likely from the speaker's point of view.
In the bottom sentence, the speaker thinks it's less likely that she's going to wait
