went to Kenya last summer. ... past simple (specific from past, past simple) I play tennis every Friday. ... present simple (routine, simpler now) He isn`t studying at the moment. ... present continuous (something does not happen / happens at the moment of speaking, continuous time is continuous) They What were you doing yesterday between 3.00 and 5.00? ... past continuous (longer activity from past - past continuous) I`ve started this exercise. ... present perfect (something has started in the past and may continue) i`ll go to university. ... future with will (spontaneous utterance in the future, future simple) Is it going to rain tomorrow? ... be going to (going to refer to the nearest plans / intentions, here it is about the weather difficult to predict) I'm visiting my grandparents next weekend. ... present continuous for future (we are a contract, that's why our intention is not going to change, it's a continuous future applied to the future.
