名人教英文：tenses动词之「时」
the word "tense" means "time". it is associated with a verb to denote the time of the action, its continuance or completion.
the precision of the english language is largely attributable to the different tenses being used to convey a sense of time in which certain actions take place.
there are basically three main groups of tenses and their variants (1) , namely:
◆the present tense: simple present, present continuous, present perfect tense. (2)
◆the past tense: simple past, past continuous, past perfect tense. (2)
◆the future tense: simple future, future continuous, future perfect tense. (2)
the general rules are:
a)we choose a particular tense to show the time of a certain action or for a particular effect; and
b)to avoid confusion, we do not switch back and forth from one tense to another without good reason.
for example: the present tense is used to describe a present event or something which is perpetually true as in the statement : "the sun rises in the east". the past tense is used to describe a past event and the future tense is used to describe a future event. thus, the tense in english denotes with precision the time of the action, the continuance of the action and the completion of the action.
however, the technique of using the present tense to describe a past event is sometimes used by writers to show immediacy (3) of the action taking place.