ERLENMEYER FLASK

Bunsen Burner

LABORATORY INSTRUMENTS

BEAKER

CONTINUATION OF HOMEWORK

• Must

We use must to express something that you or other people think it is a serious obligation. This form is used only in the present and future.

Examples:

We must pay our taxes.

Children must obey their parents.

We use must to express speculations, when you are 100% (or almost 100%) sure that something is correct or true.

Examples:

It must be raining. Listen!

My father must be at the office. His car is in front of his office.

These modals follow the same patterns:

Affirmative pattern

Subject + modal auxiliary + verb in simple form + complement.

I can speak English well.

We could run fast 10 years ago.

We must pay our taxes.

We should study everyday.

Negative pattern

Subject + modal in negative + verb in simple form + complement.

I can´t play the guitar.

They couldn´t swim 5 years ago.

We mustn´t destroy trees.

She shouldn´t drive so fast.

Interrogative form

Modal auxiliary + subject + verb in simple form + complement + ?

Can you dance salsa?

Could he drive 5 years ago?

Must we enter now?

Should people save water?

MODAL VERBS

We use the modal verbs when we want to express ability, suggestion, obligation,prohibition and request.

The most common are:

• CAN

We use can to express an ability or possibility.

Examples:

I can speak English well.

We can go to the library today.

• SHOULD

We use should to give advice, a recommendation.

Examples:

You are sick. You should go to the doctor.

We should study everyday.

• COULD

We use could to express ability to do something in the past.

Examples:

I could walk when Iwas 1 year old.

We could run fast 10 years ago.

We also use could to express possibility. It is not as strong as "might" or "may". It is just a simple possibility.

Examples:

We could stay home and watchtv.

She could go to France when she arrives to Europe.

16/04/10

EXERCISES

Should = Deberias

Could = Podrías

We should sell pop corns.

We shouldn´t sell chiles en vinagre?

I think that you should sell chips.

We could make a virus.

How you´ve been? ¿Como has estado?

What happend.
How was? Como estuvo.
We could make a virus.
What´s going on? ¿Qué esta pasando?

SHOULD, SHOULDN´T, WHY DON´T YOU...?

• We use should to give advice, to express that something is a good idea.
• We use should not (shouldn´t) to give advice in negative form, to express that something is not a good idea.

Examples:

I am sick.

You should go to the doctor.

You shouldn´t take any medicine without prescription.

Should I stay home?

09/ o4/10