8.19 saying when a situation began

If you want to say that a situation started to exist at a particular time and still exists, you use 'since' or 'ever since'. In the time clause, you use the simple past tense.

You also use 'since' or 'ever since' to say that a situation started to exist at a particular time, and still existed at a later time. In the time clause, you use the simple past tense or the past perfect tense.

If you are mentioning someone's age at the time when a situation started, you always use the simple past tense.

'Since' is also used in reason clauses. This is explained in paragraph 8.50.