5775 時態 - 過去不完成式

    過去不完成式通常代表一個連續或重覆的行動, 現在時態可譯為 "they are
    asking," 而過去不完成式則譯為 "they kept on asking."

    不過在"to be,"動詞中, 過去不完成式則表示去過一個單一的事件,
    而不是連續或重覆的動作.

5775 Tense - Imperfect

    The imperfect tense generally represents continual or repeated
    action.  Where the present tense might indicate "they are
    asking," the imperfect would indicate "they kept on asking."

    In the case of the verb "to be," however, the imperfect tense
    is used as a general past tense and does not carry the
    connotation of continual or repeated action.