2. 外语
  3. We all know that programming language is the system of syntax, grammar, and symbols or words used to give instructions to a comp

We all know that programming language is the system of syntax, grammar, and symbols or words used to give instructions to a comp

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问题    We all know that programming language is the system of syntax, grammar, and symbols or words used to give instructions to a computer. Because computers work with binary numbers, first-generation languages, called machine languages, required the writing of long strings of binary numbers to represent such operations as add, subtract, and compare. Later improvements allowed octal, decimal, or hexadecimal representation of binary strings. It is difficult to write error-free programs in machine language; many languages have been created to make programming easier and faster. Symbolic, or assembly, languages-- second-generation languages---- were introduced in the early 1950s. They use simple mnemonics such as "A" for add or "M" for multiply, which are translated into machine language by a computer program called an assembler. An extension of such a language is the macro instruction, a mnemonic (such as "READ" ) for which the assembler substitutes a series of simpler mnemonics. In the mid-1950s, a third generation of languages came into use. Called high-level languages because they are largely independent of the hardware, these algorithmic, or procedural, languages are designed for solving a particular type of problem. Unlike machine or symbolic languages, they vary little between computers. They must be translated into machine code by a program called a compiler or interpreter. The first such language was FORTRAN (FORmula TRANslation), developed about 1956 and best used for scientific calculation. The first commercial language, COBOL (Common Business Oriented Language), was developed about 1959. ALGOL (ALGOrithmic Language), developed in Europe about 1958, is used primarily in mathematics and science, as is APL (A Programming Language), published in 1962. Pl/l (programming Language 1), developed in the late 1960s, and ADA (for Ada Augusta, countess of Lovelace, biographer of Charles Babbage), developed in 198 l, are designed for both business and scientific use. For personal computers the most popular languages are BASIC (Beginners All-purpose Symbolic Instruction Code), developed in 1967 and similar to FORTRAN, and Pascal (for Blaise Pascal, who built the first successful mechanical calculator), introduced in 1971 as a teaching language. Modula 2, a Pacal-like language for commercial and mathematical applications, was introduced in 1982. The C language, introduced (1972) to implement the Unix operating system, has been extended to C ++ to deal with the rigors of object-oriented programming. Fourth-generation languages are nonprocedural. They specify what is to be accomplished without describing how. The first one, FORTH, developed in 1970, is used in scientific and industrial control applications. Most fourth-generation languages are written for specific purposes. Fifth-generation languages, which are still in infancy, are an outgrowth of artificial intelligence research. PROLOG (PROgramming Logic) is useful for programming logical processes and making deductions automatically.
   Many other languages have been designed to meet specialized needs. GPSS (General Purpose System Simulator) is used for modeling physical and environmental events, and SNOBOL (String-Oriented Symbolic Language) and LISP (LISt Processing) are designed for pattern matching and list processing. LOGO, a version of LISP, was developed in the 1960s to help children learn about computers. PILOT (Programmed Instruction Learning, Or Testing) is used in writing instructional software, and Occam is a nonsequential language that optimizes the execution of a program’s instructions in parallel processing systems.
In the late 1950’s, for the first time a computer programming language _____.
选项 A、began using binary numbers
B、was used to implement the Unix operating system
C、was put into the market
D、was used for modeling physical and environmental events
答案C
解析 语意题。1959年即the late l950’s而put into the market即成为商业语言(commercial language)，因此C为正确答案。
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