Can you explain the differences between present continuous, simple present, simple past, and past continuous?

Simple vs. Continuous tells us about action. Present tense tells us that something can happen but doesn't mean it is happening. Continuous tells us that something is happening.

Past vs Present tells us about time.

And so:

Present Simple - I study - ex. I study math.

We know that the person speaking at any given time might be studying math, but we don't know if they are right now.

Present Continuous - I am studying - ex. I am studying math.

We know that the person speaking has a math book open and is actively studying math.

Past Simple - I studied - ex. I studied math.

We know that the person speaking at some point in the past studied math. It could have been earlier in the day, last month, or 80 years ago. We just don't know.

Past Continuous - I was studying - ex. I was studying math when the phone rang.

We know the speaker was recently studying math but that something happened to divide up the time (for all we know, the person could still be studying math).

Present Continuous:

• Used to describe actions that are happening right now at the moment of speaking or actions that are ongoing.
• Formed by using the present tense of the verb "to be" (am/is/are) followed by the base form of the main verb with the -ing suffix.

Simple Present:

• Used to describe habits, general truths, or actions that regularly occur.
• Formed by using the base form of the verb, with the addition of -s or -es for third-person singular subjects.

Simple Past:

• Used to describe actions that happened at a specific point in the past and are now completed.
• Formed by using the past tense form of the verb, which typically ends in -ed for regular verbs, while irregular verbs have specific past tense forms.

Past Continuous:

• Used to describe actions that were ongoing or in progress at a specific point in the past.
• Formed by using the past tense of the verb "to be" (was/were) followed by the base form of the main verb with the -ing suffix.

In summary, the present continuous describes actions happening now or ongoing, the simple present describes habitual actions or general truths, the simple past describes completed actions in the past, and the past continuous describes actions that were ongoing at a specific point in the past.