To be+ Verb(ING) or not To be+ Verb(ING)? Was that your question?

Many verbs are used in continuous tenses. Here are some examples:

Present continuous - I'm jogging at the moment.

Past continuous - Jack was calling her when I arrived.

Future continuous - I will be traveling to London in one hour.

Present perfect continuous - I've been looking for you for 3 days.

Normally, the usages of the continuous tenses reflect
an action or process that is happening at a particular moment in time. 

The focus when using continuous tenses is always on an action/process in progress. However, there are some important exceptions to using continuous tenses. 

Most importantly, there are a number of common non-continuous verbs that are never or rarely used with continuous forms. 

These verbs are usually things you cannot see somebody doing and fall into a few categories:

• Mental / Emotional States

believe

dislike

doubt

imagine

know

like

love

hate

prefer

realize

recognize

remember

suppose

understand

want

fear

envy

mind

wish

Analyse this context:

The other day my wife and I arrived home somewhat in a good mood, we didn't expect to have the surprise we had...

Our dog, who normally stays inside when we are out for short periods, had tore one of our cushion pillows apart.

My wife got really upset and yelled at him:

'' I ______________ in what you've done here!!

       (NOT to believe)

Here, specially for Brazilian learners, is common to be naturally  induced to a mistake on using the continuous tense, as in (am believing). However, the correct form for this non-continuous verb is:

'' I don't believe in what you've done here!!

        (NOT to believe)

• Sense

appear

hear

see

seem

smell

sound

taste

Examples

I saw him when the train arrived.  NOT   I was seeing him when the train arrived.

It tastes strange.  NOT  It is tasting strange.

Did you hear that?  NOT  Are you hearing that?

• Communication

agree

astonish

deny

disagree

impress

mean

please

promise

satisfy

surprise

Examples

You astonish me!   NOT   You are astonishing me!

I'm afraid I disagree with you.   NOT  I'm afraid I am disagreeing with you.

I meant to tell him yesterday afternoon.   NOT  I was meaning to tell him yesterday afternoon.

• Other States

be

belong

care

concern

consist

contain

cost

depend

deserve

exist

fit

include

involve

lack

matter

need

owe

own

possess

seem

Examples

It depends on how much it costs.   NOT  It is depending on how much it is costing.

She said it involved a lot of work.   NOT  She said it was involving a lot of work.

It doesn't matter.   NOT   It isn't mattering.

There are also a number of verbs that don't take the continuous forms in one meaning but DO take the continuous forms in other meanings. Here are some of the most important:

Non-Continuous Meanings

feel = 'have an opinion' - He feels he should get a second chance.
see = 'understand' - I see what you mean.
think = 'have an opinion' - I think we should leave immediately.
appear = 'look like' - That appears to be stale.
look = 'seem' - It looks impossible!
taste = 'have a taste' - That tastes yummy!

Continuous Meanings

feel = 'feel physically' - I'm feeling awful this afternoon.
see = 'visit' - She's seeing a doctor this morning.
think = 'use the brain' - He's thinking hard about the problem.
appear = 'be on stage / perform' - Jack Daniels is performing at the Paramount tonight.
look = 'stare at' - I'm looking at that strange man.
taste = 'use the mouth' - The cook is tasting the sauce!