Lessons 3 - 4

3 - Types of Computer Systems

A. From mainframes to wearable computers Mainframe

server

desktop PC IBM PC Apple Macintosh

laptop (notebook)PC Thin Film Transistor (TFT) screen touchpad Universal Serial Bus (USB) ports battery packs

3 - Types of Computer Systems

A. From mainframes to wearable computers tablet PC PDA - Personal Digital assistant

handheld devices palmtops pocket PCs

Input via stylus touch screen handwriting recognition voice recognition wireless technology

wearable computer

3 - Types of Computer Systems

4 - Input devices: type, click and talk!

A. Interacting with your computer Input devices - definition

touchpadtouchpad

trackballtrackball

4 - Input devices: type, click and talk!

B. The keyboard Groups of keys

Alphanumeric keys Letters and numbers

Numeric keypad Numeric and editing keys

Function keys Cursor keys

Arrow keys, Home, End, Page Up, Page Down Dedicated keys

Ctrl Caps lock Enter (Return) Backspace

4 - Input devices: type, click and talk!

Modal Verbs Modal verbs are a special form of verbs that we use

before other verbs to express certain meanings: permission ability possibility certainity

Modal verbs are: can, could, may, might, shall, should, will, would, must, ought to

Verbs similar to modals are: used to, had better, need not (needn’t)

Past and future of modals: be able to, have to

Modal Verbs

Modal Verbs

Modal Verbs must In affirmative sentences we use must when we mean: “This is necessary.”I must go to the library tomorrow.

We must fill in this form.

“This is a very good idea.”

You must visit us while you are in Paris.

We must see you again.

In questions, we use must when we mean: “Is this really necessary?”Must you talk so loud?

Must we tell the police when we change the address?

Modal Verbs must not (mustn’t) and need not (needn’t) We use must not when we mean:

“Do not do that!”

You must not smoke here!

You must not wake the baby.

We use need not when we mean:

“This is not necessary.”

We need not pay now, we can pay later.

We need not hurry - we are early!

Affirmative “need” is not a modal verb.He needs to go now.

Modal Verbs have to It is not a modal verb, but we use have to like must

and do not have to like need not. We use have to when we want to say/ask: “This is

necessary.”/”Is this necessary?” (like must)

You have to drive on the left in Britain.

Does she have to study for her exam?

We use do not/does not have to when we want to say “This is not necessary.” (like need not)

You do not have to phone her, she knows already.

We normally use have to, not must when we talk about rules and laws.

Modal Verbs had to | will have to We use had to for the past and will have to for the

future of must and have to.

Did you have to learn Franch in school?

I had to answer all the questions.

I did not have to make lunch yesterday.

I will have to clean my flat tomorrow.

Will you have to start school next month?

He will not have to pass the exam.