MODAL VERBS

HAVE GOT TO

"Have got to" is used to express necessity and obligation.

Examples:

• Drivers have got to get a license to drive a car in the US. necessity
• I have got to be at work by 8:30 AM. obligation

Using "Have Got to" in Present, Past, and Future

Most modal verbs behave quite irregularly in the past and the future. Study the chart below to learn how "have got to" behaves in different contexts.

Use	Positive Forms 1. = Present   2. = Past   3. = Future	Negative Forms 1. = Present   2. = Past   3. = Future	You can also use:
have got to necessity	1. People have got to be on time if they want to get a seat in the crowded theater. 2. SHIFT TO "HAVE TO" You had to be on time if you wanted to get a seat in the crowded theater. 3. You have got to be there on time tonight if you want to get a seat in the crowded theater.	1. SHIFT TO "HAVE TO" People don't have to be there on time to get a seat. 2. SHIFT TO "HAVE TO" You didn't have to be there on time to get a seat. 3. SHIFT TO "HAVE TO" You won't have to be there on time to get a seat.	have to, must
haven't got to future obligation		Haven't you got to be there by 7:00? Haven't you got to finish that project today? "Haven't got to" is primarily used to ask about future obligations. It can be used in statements, but this is less common.	Don't you have to

MODAL VERBS

BE ABLE TO 

Although we look at be able to here, it is not a modal verb. It is simply the verb be plus an adjective (able) followed by the infinitive. We look at be able to here because we sometimes use it instead of can and could.
We use be able to:

• to talk about ability

Structure of Be able to

The structure of be able to is:
subject + be + able + infinitive

	subject	be main verb	able adjective	infinitive
+	I	am	able	to drive.
-	She	is not	able	to drive.
		isn't
?	Are	you	able	to drive?

Notice that be able to is possible in all tenses, for example:

• I was able to drive...
• I will be able to drive...
• I have been able to drive...

Notice too that be able to has an infinitive form:

• I would like to be able to speak Chinese.

Use of Be able to

Be able to is not a modal auxiliary verb. We include it here for convenience, because it is often used like "can" and "could", which are modal auxiliary verbs.

be able to: ability

We use be able to to express ability. "Able" is an adjective meaning: having the power, skill or means to do something. If we say "I am able to swim", it is like saying "I can swim". We sometimes use "be able to" instead of "can" or "could" for ability. "Be able to" is possible in all tenses - but "can" is possible only in the present and "could" is possible only in the past for ability. In addition, "can" and "could" have no infinitive form. So we use "be able to" when we want to use other tenses or the infinitive. Look at these examples:

• I have been able to swim since I was five. (present perfect)
• You will be able to speak perfect English very soon. (future simple)
• I would like to be able to fly an airplane. (infinitive)

You can notice it in the following examples.

I CAN WRITE IN FRENCH.   

It´s a possibility

I AM ABLE TO WRITE IN FRENCH.

It may be when we could be in France so We need to write to someone from there.