This is a tough one to explain if you are not an English teacher. I have always worked. Exercise has always been important to me. This tense implies an ongoing action that started sometime in the past. I had always worked. Exercise had always been important to me. This tense implies an activity, but not a specific episode, that used to occur but doesn't anymore. Future means that the activity hasn't happened yet but the intention is there. Your grammar on one of your examples is incorrect and may be confusing you. "I will never be a mechanic". Hope this helps a little.

Hi Paulina, PRESENT PERFECT TENSE They are formed using "has", "have" and another verb in the past participle form. Examples are: has done / have taken / have spoken etc. Tenses are used to attach the dimension of time to an action. Present Perfect Tense is used to describe an action that happened in the past, and the effect of that action is still present. Example: I have taken my breakfast (He has bought the tickets. The purchase took place earlier but the tickets are still in my possession now. The fact that he has bought still stays.) PAST PERFECT TENSE Past Perfect tense can be used to indicate an even earlier action in the past. For example, you are having dinner (7pm). You told your friend, "I had finished my work before I took a cab home." You completed your work EARLIER in the past (4pm). Then you took a cab home (5pm). I hope this helps. Cheers, Lance