The Imperfect is in some ways the opposite of the Perfect. Whereas Perfect emphasizes completion, Imperfect emphasizes continuation (or, in one case, a completion without success: i.e., 'the attempted').
The Imperfect tense is a past tense, and it occurs only in the indicative mood. Thus it will always have an augment.
USES OF THE IMPERFECT
TENSE:
The imperfect tense is used to express a range of action in which something
more than the mere act is intended to be expressed. The illustration below
gives some sense of this range.