但从格式塔突显原则分析，非完成动词进行体是进行体的标记形式，非常规结构暗示着特殊意义。

But the analysis in gestalt principles shows that imperfective progressive is its marked form, and it implies certain special meaning.

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本文跟据英语动词词汇意义所暗含的体态特征，将英语动词分为终结动词、完成动词、活动动词、持续动词四类。

English verbs can be divided into four groups: achievement verb, accomplishment verb, activity verb and state verb. According to the aspect characteristics contained in English verbs.

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while I was washing my hair中的动词是过去未完成时。

In 'while I was washing my hair', the verb is in the imperfect.

《牛津词典》