Tense

Aspect

Things can and do happen now, in the future or in the past. The tenses simply show the time of an action or state of being as shown by a verb. The verb ending is changed (conjugated) to show what time it is referring to.

In English there are ONLY two tenses: past & present. Time, however, can be split into three periods:

• The Present (what you are doing)
• The Past (what you did)
• The Future (what you are going to do, or hope/plan to do).

The tenses we use to show what time it is that we are talking about are split into the Simple, Continuous and Perfect tenses. In English we use two tenses to talk about the present and six tenses to talk about the past. There are several ways to talk about the future some of which use the present tenses, these are:

​Useful practice quizzes here for verb tense:
http://www.englishpage.com/verbpage/verbtenseintro.html

                From the Latin, "how [something] looks"  = Aspect

This is when the form of the verb indicates completion, duration, or repetition of an action. The two primary aspects in English are the perfect (sometimes called perfective) and the progressive  (also known as the continuous form). These two aspects may be combined to form the perfect progressive.

So, what exactly if the difference between Tense and Aspect
"Traditionally both aspects [perfect and progressive] are treated as part of the tense system in English, and we commonly speak of tenses such as the present progressive (e.g. We are waiting) or even the past perfect progressive (e.g. We had been waiting), which combines two aspects. There is a distinction to be made, however, between tense and aspect. Tense is more concerned with past time versus present time and is based on morphological form (e.g. write, writes, wrote); aspect is concerned with duration, and in English is a matter of syntax, using parts of be to form the progressive, and of have to form the perfective."
(Sylvia Chalker and Edmund Weiner, Oxford Dictionary of English Grammar. Oxford University Press, 1994)