“Do not dwell in the past, do not dream of the future, concentrate the mind on the present moment.” - Hindu Prince Gautama Siddharta, Founder of Buddhism

Main verbs are either past tense or present tense.

Past Tense - Actions or states in the past.

Present Tense - Actions or states at the time of speaking.

The present tense is in effect when any time is expressed as the present or if the fact is relevant today. The past tense excludes the present and only covers events that took place at a definite time or in the past. Even if 90% of the sentence is written in the past tense, just one use of a present tense word makes the whole sentence present tense.