The imperfect is used for a simple future tense. (Genesis 2:18) "I will make for him a helper who corresponds to him."
The imperfect is used for action that is going on in the present. (Genesis 37:15) "The man asked him, 'What are you seeking'?"
The imperfect is used to express general truths, which in English are typically expressed with a present tense. (This use is like the gnomic perfect.) (Proverbs 10:1) "A wise son brings joy to his father."
The imperfect is used for customary actions in the past. (1 Samuel 1:7) "This is what he did year after year."
The imperfect is used for actions that have just begun in the past. (Gen 2:6) "Rain clouds began to arise from the earth."
The imperfect is used for actions that are possible. (Jonah 3:9) "Who knows? God may relent."
The imperfect is used for actions that a subject is capable of carrying out. (Genesis 6:21) "And take for yourself what ever you want from that which can be eaten."
The imperfect is used for actions that a subject is obligated to carry out. (Exodus 4:15) "I will teach you what you must do."
The imperfect is used for actions that a subject has permission to carry out. (Psalm 15:1) "Who may dwell in his holy mountain?"
The imperfect is used for giving instructions. (Leviticus 19:32) "You are to rise in the presence of the aged."
The imperfect is used for giving negative instructions or prohibitions. (Exodus 20:3) "You must not have other Gods before me."