Touchscreen,trackball,touchpad, webcam

1. A………. is a stationary device that works like a mouse turned upside down. You roll the ball with your hand to move the pointer on the screen.

2. Interactive……….are used in museums, information centres and Internet kiosks. You use your finger to point directly to objects on the screen.

3 A……….is used to send live video images via the Internet.

4 A……….is found on notebook PCs. You use it by pressing the sensitive pad with a finger.

Exercise 3. Complete these sentences with the correct 'mouse action'.

1. To start a program or open a document you………on its icon - that is, you rapidly press and release the mouse button twice.

2. If you want to select a menu option, you just……….on the left button.

3.If you want to find the commands for a particular text, image, etc., you have to……….on it.

4.If you want to move an object, press the button and………..the object to the desired location.

Exercise 4. Read and correct the false statements.

1.The images shown on a monitor are not generated by the video card.

2.All visible colours can be made from mixing the three primary colours of red, yellow and blue.

3.Typical CRT-based displays occupy less space than LCD displays.

4.Active-matrix LCDs do not use a technology called thin film transistor or TFT.

5.The size of the screen is measured horizontally.

Exercise 5. Match each term with the correct definition.

1.phosphors	a.the frequency at which a monitor renews its image, measured in Hz
2.LCD screen	b.a flat-panel display which works by emitting light through a special liquid
3.pixel	c.the space between a display’s pixels
4.dot pitch	d.the smallest element in a displayed image
5.refresh rate	e.materials that emit light and produce colours when they are activated by an electron beam