Распространенные ошибки
As a rule, verbs denoting a state rather than an act have no continuous forms, like understand, know, believe, like, love, belong, prefer, consist, mean, hear, see, etc.
Don't use the simple past tense after to.
We also use the present continuous for the future when something is pre-arranged or expected with some certainty: Lorna is arriving tomorrow at six. Tom and I are eating out tonight
Express an improbable condition by the past tense and use the conditional in the main clause. This use of the past tense doesn't indicate a time but a degree of probability.
Use the simple past tense to express a habit in the past, and not the past continuous
Use the past continuous tense to describe events in the past happening at the time another action took place: I was walking to school when I met him.