[Grammar] Present tense(do, be doing, be being done)

Present continuous(I am doing)

We use the continuous for things happening at or around the time of speaking. The action is not complete.

e.g) 

The water is boiling. Can you turn it off?

Listen to those people. What language are they speaking?

Let's go out. It isn't raining now.

I'm busy. What are you doing?

I'm getting hungry. Let's go and eat.

Kate wants to work in Italy, so she's learning ltalian.

The population of the world is increasing very fast.

We use the continuous for temporary situations 

e.g)

I'm living with some friends until I find a place of my own.

You're working hard today. Yes, I have a lot to do.

Present simple(I do)

We use the simple for things in general or things that happen repeatedly.

e.g)

Water boils at 100 degrees Celsius.

Excuse me, do you speak English?

It doesn't rain very much in summer.

What do you usually do at weekends?

I always get hungry in the afternoon.

Most people learn to swim when they are children.

Every day the population of the word increases by about 200,000 people.

We use the simple for permanent situations

e.g)

My parents live in London. They have lived there all their lives.

Joe isn't lazy. He works hard most of the time

We use continuous forms for actions and happenings that have started but not finished (they are eating./ It is raining etc.). Some verbs are not normally used in this way. We don't say 'I am knowing' or 'they are liking' ; we say 'I know', 'they like'

The following verbs are not normally used in the present continuous:

like / want / need / prefer

know / realize / suppose / mean / understand / believe / remember

belong / fit / contain / consist / seem

e.g)

I'm hungry. I want something to eat.

Do you understand what I mean?

Anna doesn't seem very happy at the moment.

When think means 'believe' or 'have an opinion' , we do not use the continuous:

e.g)

I think Mary is Canadian, but I'm not sure.

What do you think of my plan?

When think means 'consider' , the continuous is possible:

e.g)

I'm thinking about what happened. I often think about it.

Nicky is thinking of giving up her job. 

We normally use the present simple (not continuous) with these verbs(see hear smell taste)

e.g)

Do you see that man over there?

This room smells. Let's open a window.

You can use the present simple or continuous to say how somebody looks or feels now:

e.g)

You look well today. or You're looking well today.

How do you feel now? or How are you feeling now?

but I usually feel tired in the morning. (not I'm usually feeling)

Passive Present continuous(be being done)

active : am/is/are + (do)ing

passive : am/is/are + being (done)

e.g)

Somebody is cleaning the room at the moment.

The room is being cleaned at the moment.

There's somebody walking behind us. I think we are being followed.

(In a shop) Can I help you? No, thanks. I'm being served.

The passive of doing/seeing etc. is being done / being seen etc. Compare:

active   : I don't like people telling me what to do.

passive : I don't like being told what to do.

e.g)

I remember being taken to the zoo when I was child. (=I remember somebody taking me to the zoo.)

Steve hates being kept waiting. ( = He hates people keeping him waiting.)

We managed to climb over the wall without being seen. ( = without anybody seeing us.)