Countable nouns have singular and plural forms.

可数名词有单数和复数之分。

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Usted and ustedes are respectful and formal words used to express you , in the singular and plural forms.

您和您们是正式和尊敬的称呼，有单数和复数之分。

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In addition, it explains some aspects which are easy to be used incorrectly, such as articles, prepositions, numerals, singular and plural forms of nouns and punctuation marks.

对英文题名的结构和字数要求以及英文摘要的时态和语态进行了分析，对容易出错的冠词、介词、数词、单复数、标点符号等问题进行了说明。

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