'Am', 'is', 'are', 'was' and 'were' are the finite forms of 'be'; 'being' and 'been' are the non-finite forms.
am、is、are、was和were是be的限定形式;being和been是非限定形式。
《牛津词典》
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This article categorizes, analyzes, and USES concrete examples to expound the compound words which are structured from non-finite verbs of Modem Uygur, and points out their functions in the language.