Answer: 1. Action happening now, today ----> present tense
2. Action completed during the present time ---> present perfect tense
3. Action expected to happen ----> future tense
4. Action completed before a set time in the past ----> past perfect tense
5. Action completed before a set time in the future ----> future perfect tense
6. Action completed in an earlier time period ----> past tense
Explanation: There are several verb tenses in English. Present tense is used to refer to an action or event that is taking place right now, that is to say to refer to an action or event that has not been completed yet. The present perfect tense, on the other hand, can be used to refer to an action that started in the past and was completed during the present time. The present perfect tense is formed with the modal verb "have" plus the past participle of a verb. Future tense is used to make reference to an action or event that has not taken place yet because it is expected to occur in the future. Future tense is mainly formed with the modal verb "will" plus the root form of a verb. In contrast, future perfect tense is formed with the verb "will" plus "have" plus the past participle of a verb and it is used to refer to an action or event that will be considered as completed in the future. Moreover, the past tense is used to refer to an action or event that already happened in the past, while the past perfect tense, which is formed with "had" plus the past participle of a verb, is used to refer to something that took place before another past action or before a point in time set in the past.