We use the present simple to talk about things and situations that are generally true

Irregular verbs

Irregular verbs are verbs that don't follow the rule of adding the inflection -ed/d to form the simple past or past forms.
There are quite a few irregular verbs in English; let's look at some examples.

Examples of irregular verbs

I grow (present tense) → I grew (past tense) → I have grown (past participle)
I am (present tense) →I was (past tense) →I have been (past participle)
I go (present tense) → I went (past tense) →I have gone (past participle)
I break (present tense) →I broke (past tense) →I have broken (past participle)
I quit (present tense) → I quit (past tense)→ I have quit (past participle)
These examples show how varied irregular verbs can be .For regular verbs we can simply add -ed/-d for to the base form of a verb (Verb 1) for both the past simple tense (verb 2) and past participle (verb 3).For example, I dance (present tense / base form)→I danced(past tense)→I have danced(past participle).However, things aren't as simple in the case of irregular verbs which often differ in spelling between the present, past, and past participle. Unfortunately, there is no rule for irregular verbs, you simply have to remember them!
The past participle is the form of the verb which we see in the perfect and passive forms. It expresses a completed action and is often preceded by an auxiliary verb such as has / had. For example, 'you have eaten 'or' he has left'.

Aspect

Each of the three main tenses (past, present, and future) is divided into four aspects. Aspect shows the time-related characteristics of a sentence such as whether a verb is on going, repeated, or completed.
We can classify tenses into four different types:simple, progressive (continuous), perfect, and perfect progressive (continuous).
Let's take a look at the functions and some examples of these aspects in more detail.

Simple

The simple tense simply expresses that an action has taken place in the past / present / future .In other words, it states a fact. There are no aspects so we are not given information about 'how' the verb is done eg.'I walked'(simple past),'I walk'(simple present), 'I will walk'(simple future).

Perfect (or 'perfective')

The perfect aspect expresses acompleted action, one that occurred prior to a specific point in time. We can form the perfect aspect using' had', 'has', or 'will have'+ the past participle of the verb.
The past perfect looks back from a point of time in the past, eg.'I had walked'.
The present perfect looks back from the present time, eg.'I have walked'.
The future perfect looks back from a time in the future, eg.'I will have walked'.

Progressive / continuous

The continuous aspect expresses an ongoing, uncompleted action. We form the progressive aspect using the correct form of 'be'(depending on the tense) and the inflection -ing added to the main verb, eg.'I was walking'(past continuous),'I am walking'(present continuous), or 'I will be walking'(future continuous).

Perfect continuous (or 'progressive')

The perfect continuous aspect expresses that an action started in the past is continuing into the present. A perfect continuous sentence is formed with the auxiliary have / has / had with the auxiliary been(past participle) together with the main verb eg 'walking'(conjugated in the present tense).For example'I had been walking'(past perfect continuous), 'I have been walking'(present perfect continuous), or 'I will have been walking'(future perfect continuous).