Tense vs Aspect
Tense and Aspect are two words used in English Grammar that should be understood carefully. This is due to the fact they are two grammatical terms that show differences between them.
The verb-forms which show differences in time are called tenses. It is important to know that tenses are formed by changing the verb as in the sentences:
1. I know him very well.
2. She worked all through the night.
In both the sentences given above you can see that the verbs have been changed to convey time and hence the first sentence is in present tense and the second sentence is in past tense.
It is equally important to know that tenses are formed also by adding auxiliary verbs as in the sentences:
1. He will work hard to get the desired result.
2. She had done a great job.
In both the sentences given above you can see that the speaker has added auxiliary verbs such as ‘will’ in the first sentence and ‘had’ in the second sentence.
On the other hand aspect refers to the changes in verb-forms that express other ideas besides differences of time. For instance, the ‘perfect’ verb-form can be employed to emphasize the idea of completion as in the sentence ‘I have finished the job’. Also observe the sentence ‘He will have scored 100 centuries by the time he retired.’ This is the purpose of using aspect in English grammar.
It is interesting to note that the present perfect tense often suggests that a past event is still being remembered, being talked about and is still present in some way as in the sentence ‘the Japanese have progressed well in technology’. These are the important differences between the two grammatical terms, namely, tense and aspect.