What you mean by future tense  and  past  teanse

future tense In grammar, a future tense is a verb form that generally marks the event described by the verb as not having happened yet, but expected to happen in the future.   past tense  

1. The past tense is a grammatical tense whose principal function is to place an action or situation in past time. In languages which have a past tense, it thus provides a grammatical means of indicating that the event being referred to took place in the past.