Exploring your options to turn off the PC

To put your PC into Stand By mode, follow these steps:

 

A

Click the Start button.

 

B

Save your work!

 

C

Click the Shut Down button at the bottom of the Start panel. The Turn Off Computer dialog box appears.

 

D

Click the Stand By button. The computer then appears to have turned itself off, but it's really just resting.

 

E

Close your programs.

 

55 Use sequence words or perfect constructions as in the model to tell how to put your computer into Sleep mode. Then tell how to wake up the computer.

Model:

First click on the appropriate tab. Then enter the selection criteria. Finally click on the Find button.

Having entered the selection criteria, click on the find button. Once the selection criteria have been entered, click on the find button.

Here is an instruction for fitting a new motherboard. Some phrases are missing. Put phrases (A-E) in their proper places (1, 4, 7, 9, 12).

 

1 Turn off the computer and open the case. 2 _____________________ 3 Disconnect wires and cables and label them with tape. 4 ______________________ 5 Take out the add-in card. 6 Remove the screws holding the motherboard. 7 _________________________ 8 Add the CPU and memory to the new motherboard. 9 ________________________ 10 Replace the screws. 11 Replace cards and cables. 12 _________________________

A Check the new motherboard to ensure it fits the system case.   B Lift the motherboard carefully from the case.   C Unplug all external peripherals.   D Insert the new motherboard.   E Switch on the computer monitor.

 

57 Read an article from the book “Windows XP Headaches: How to Fix Common Problems in a Hurry” and fill in the blanks with the link words:

also, then, if, until, which, unless, before, and, either.

 

Cause: Windows XP may stop responding due to a hardware or software conflict.

 

The Pain Killer: To solve the problem, press CTRL+ALT+DEL, (1)________opens Task Manager. Look on the Applications tab, select the application that is Not Responding, and (2)_______ click the End Task button. (3)_________ that doesn't work, press CTRL+ALT+DEL two times in a row to restart your computer. If that doesn't work (4)________, hold down the computer's power button for five to ten seconds (5)___________ the computer restarts. If that (6)__________ does not work, unplug your computer, wait ten seconds, and then plug it back in (7)__________ restart it.

Never unplug your computer from the power source to turn it off (8)_________ you already have tried everything else. Then, make sure you wait

 

58 Write an instruction for any computer operation.

59 Read the text and answer the questions

1 What is the difference between programming languages and natural languages? What is their similarity?

2 Why have the attempts to design one " universal" computer language failed?

3 What do syntax and semantics describe?

4 What determines the use of a certain programming language?

PROGRAMMING LANGUAGES

A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer.

A prominent purpose of programming languages is to provide instructions to a computer. As such, programming languages differ from most other forms of human expression in that they require a greater degree of precision and completeness. When using a natural language to communicate with other people, human authors and speakers can be ambiguous and make small errors, and still expect their intent to be understood. However, computers do exactly what they are told to do, and cannot understand the code the programmer " intended" to write. The combination of the language definition, the program, and the program's inputs must fully specify the external behavior that occurs when the program is executed.

Many languages have been designed from scratch, altered to meet new needs, combined with other languages, and eventually fallen into disuse. Although there have been attempts to design one " universal" computer language that serves all purposes, all of them have failed to be accepted in this role. The need for diverse computer languages arises from the diversity of contexts in which languages are used:

• Programs range from tiny scripts written by individual hobbyists to huge systems written by hundreds of programmers.
• Programmers range in expertise from novices who need simplicity above all else, to experts who may be comfortable with considerable complexity.
• Programs must balance speed, size, and simplicity on systems ranging from microcontrollers to supercomputers.
• Programs may be written once and not change for generations, or they may undergo nearly constant modification.
• Finally, programmers may simply differ in their tastes: they may be accustomed to discussing problems and expressing them in a particular language.

Programming languages, like natural languages, are defined by syntactic and semantic rules which describe their structure and meaning respectively.

The syntax of a language describes the possible combinations of symbols that form a syntactically correct program. The meaning given to a combination of symbols is handled by semantics.

Below is a simple grammar, based on Lisp:

 

expression:: = atom | list
atom:: = number | symbol
number:: = [+-]? ['0'-'9']+
symbol:: = ['A'-'Z''a'-'z'].*
list:: = '(' expression* ')'

 

This grammar specifies the following:

• an expression is either an atom or a list;
• an atom is either a number or a symbol;
• a number is an unbroken sequence of one or more decimal digits, optionally preceded by a plus or minus sign;
• a symbol is a letter followed by zero or more of any characters (excluding whitespace); and
• a list is a matched pair of parentheses, with zero or more expressions inside it.

It is difficult to determine which programming languages are most used. Some languages are very popular for particular kinds of applications (e.g., COBOL is still strong in the corporate data center, often on large mainframes, FORTRAN in engineering applications, and C in embedded applications and operating systems), while some languages are regularly used to write many different kinds of applications.

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