Fill in the blanks with suitable words or expressions from the list given below, and change the form where necessary. （从下面方框中选择合适的词或表达，以其适当的形式填空。）
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A programming language, designed to facilitate the communication between human and computers, is a _____ notation _____ for describing computation in readable form. There are 3 levels of programming languages, they are____ machine language __ , which can be run directly by computer; __ assembly language ___ and _ high-level language ___. There are different high-level programming languages. Fortunately, most of them have many kinds of construct in common and vary only in the way that these must be __ written ___ . Therefore, first thing to be decided about a task is to choose which programming language is best suited for the job.