A. Present Continuous and Simple Present (2)

We can use continuous tenses only for actions and happenings (they are eating/ it is? raining, etc.). Some verbs (for example, know and like) are not action verbs. You cannot say "I am knowing" or "they are liking"; you can only say I know, they like.

The following verbs are not normally used in continuous tenses:

like   love   hate want   need   prefer
know   realize   suppose mean   understand   believe  remember
belong  contain  consist  depend  seem

Example:
1. I'm hungry. I want something to eat.
2. Do you understand what I mean?
3. Kim doesn't seem very happy right now.

B.  See  hear  smell  taste

We normally use the simple present (not continuous) with these verbs:

Example:
1. Do you see that man over there?
2. This room smells. Let's open a window.

We often use can + see/ hear/ smell/ taste:

Example:
1. Listen! Can you hear something?

C. He is selfish and He is being selfish.

He's being = He's behaving/ He's acting. Compare:

Ex: I can't understand why he's being so selfish. He isn't usually like that.
(being selfish = behaving selfishly at the moment)

but - He never thinks about other people. He is very selfish.
(he is selfish generally, not only at the moment)

We use am/is/are/being to say how somebody is behaving. It is not usually possible
in other sentences:

Example:
1. It's hot today.
2. Sarah is very tired.

D. Look and Feel

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

Example:
1. You look good today.   or   You're looking good today.
2. How do you feel now?   or   How are you feeling now?

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