1. Tense

Verbs give information about time (present and past). That is, verbs tell us when we do something. We call it tense.

2. Aspect

Verbs give information about the speaker's or writer's perspective on time (progressive and perfect). We call it aspect.

3. Voice

Verbs tell us whether the subject is the doer or receiver of the action (active and passive). We call it voice.

4. Mood

Verbs indicate the attitude or intention of the speaker. We call it mood. 

In this article, we will learn about tense and aspect. 

What is tense?

Verbs tell us "what we do". Verbs also tell us "when we do it". That is, verbs tell us the time of an action. To show different time, we use different forms of verbs. It is called tense.

Look at these sentences:

Two cats sleep on my table.

But yesterday, they slept on my bed.

In the above sentences, the verb "sleep" shows present time, and the verb "slept" shows past time. 

We say that the verb-

"sleeps" is in the present tense, and 

"slept" is in the past tense.

So, what is tense?

Tense is the form of a verb that shows the time of action. Remember that only verbs have tense.

If you want to know more, here are some definitions of tense from reputable sources.

Merriam-Webster

Cambridge Dictionary

Types of Tense

I assume that you are an advanced level learner and you more or less know about the twelve tenses of English. Now we will dive deep into the classification.

"English has two tenses, present and past." ---- Cambridge Grammar of English, Cambridge University Press

There are two tenses in English, present and past. Look at these examples:

1. Present Tense
   
2. Past Tense
3. Future Tense

Present Tense

To show present time, we use the verb as it is. We call it "present tense". The verb is in the present form. 

Look at these sentences:

1. I go to school. 
   
2. She goes to school.

We use present tense when an action happens in the present time, or when an action happens everyday or regularly. 

Past Tense

To show past time, we use the "past forms" of verbs. We call it "past tense". The verb is in the past form.

Look at these sentences:

1. I went to school. 
   
2. She went to school.

We use past tense when an action happened sometime ago [in the past time]. 

Future Tense

English verbs do not have any form of future forms. We use "shall" / "will" and the "base form of a verb" to make future tense. We use future tense to describe an action that happens in the future time [sometime after now]. 

1. I shall go to school. 
   
2. She will go to school.

Forms of Verbs Based on Tense

We use different forms of verbs for different tenses. 

Look at these sentences:

1. I do my work. [Present Tense] 
2. He does his work. [Present Tense]
3. She did her work. [Past Tense]

In sentence 1, the verb "do" shows present time. So, "do" is present tense. We say that "do" is the present form of the verb "do". 

In sentence 2, the verb "does" shows present time. So, "does" is present tense. We say that "do" is the present form of the verb "do". 

Earlier in this lesson you have learnt that English verbs tell us many things. Verbs tell us "what we do" and "when we do it".

Verbs also show whether the action is completed, progressive, or repeated. We call it aspect.

Verbs have both tense and aspect.

Verbal aspect is simple, progressive (continuous), perfect, or perfect progressive(continuous), each refers to a different fabric of time. 

Simple Tense

There are three simple tenses in English: 

(i) Present simple

(ii) Past simple

(iii) Future simple

Present Simple

We use the present forms of verbs to make present simple tenses. If the subject is third person singular, we add s or es to the verb. Present simple tenses mainly indicate present time. 

• I go. 
• He sleeps.

Past Simple

We use the past forms of verbs to make past simple tenses. Past simple tenses mainly indicate past time.

• I went.
• He slept.
  

 Future Simple

We use shall/will and the base form of verbs to make future simple tenses. Future simple tenses indicate future time.

• I shall go. 
• He will sleep.

Continuous Tense

We use an auxiliary Be + Present Participle form of a Lexical verb to make continuous tense (progressive aspect). Continuous tense means the action has started, but it is not yet complete. There are three continuous tenses. They are:

• Present Continuous
• Past Continuous
• Future Continuous

Present Continuous

We use am/is/are + Present Participle form of a Lexical verb to make Present Continuous tense. 

• I am going. 
• He is sleeping.
  

 Past Continuous

We use was/were + Present Participle form of a Lexical verb to make Past Continuous tense.

• I was going.
• He was sleeping.
  

 Future Continuous

We use shall be/will be + Present Participle form of a Lexical verb to make Future Continuous tense.

• I shall be going. 
• He will be sleeping.

Perfect Tense

We use an auxiliary Have + a past participle form of a Lexical verb to make perfect aspect. Perfect aspect means the action is just complete. There are three perfect tenses: 

• Present Perfect
• Past Perfect
• Future Perfect

Present Perfect

We use have/has + past participle form of a Lexical verb to make present perfect tense.

• I have gone. 
• He has slept.

Past Perfect

We use had + past participle form of a Lexical verb to make past perfect tense.

• I had gone.
• He had slept.

Future Perfect

We use shall have/will have + past participle form of a Lexical verb to make future perfect tense.

• I shall have gone. 
• He will have slept.

Perfect Continuous

Perfect continuous is a combination of perfect and continuous. The first part of the verb phrase indicates prefect aspect. The second part indicates continuous aspect. Perfect continuous aspect means a portion of the action is complete. There are three perfect continuous tenses. They are:

• Present perfect continuous
• Past perfect continuous
• Future perfect continuous

Present Perfect Continuous

We use have/has + been + Present participle form of a Lexical verb to make present perfect continuous tense. 

• I have been going. 
• He has been sleeping.
  

 Past Perfec Continuous

We use had + been + Present participle form of a Lexical verb to make past perfect continuous tense.

• I had been going.
• He had been sleeping.
  

 Future Perfect Continuous

We use shall have/will have + been + Present participle form of a Lexical verb to make future perfect continuous tense.

• I shall have been going. 
• He will have been sleeping.

Source:

2. The Grammar Tree [Oxford University Press]
3. Grammar Gear [Cambridge University Press]
4. Essential Grammar in Use [Cambridge University Press]
5. Cambridge Grammar of English [Cambridge University Press] by RONALD CARTER and MICHAEL McCARTHY