Simple tenses are the most common. If you’re not sure which tense to use, try a simple tense and you’ll probably be right.

Perfect tenses emphasize the result of an action. I have lived in Toronto = I don’t live there now, but I remember life in Toronto.

Continuous tenses emphasize the action.I am dancing = We don’t know when I started or when I will stop, but right now, my action is dancing.

Perfect continuous tenses emphasize an interruption. I had been studying for five hours before my sister called = For five hours, I study. I stopped this action to answer the phone.