English and ESL Instructor
The English language has 12 different tenses in total. The two most common ones are the past and present tenses:
I live in Vancouver. (Present tense)
I lived in Vancouver. (Past tense)
The meanings of these tenses are seemingly very self-explanatory, yet many students commonly misuse these tenses in academic writing assignments.
Whenever writing about a historical event or describing any past action, always use the past tense:
The Second World War began in 1939 and ended in 1945.
The high temperatures caused the pressure in the container to increase.
On the other hand, when describing events in a fictional work (e.g. a book or a film) or quoting from one, verbs should be in the present tense:
Charles Dickens' A Tale of Two Cities opens with the line, "It was the best of times. It was the worst of times."