Word order : time clauses can have an initial or final position (i.e. before or after the main clause):
1) subordinating conjunction + subject + verb…,/ subject + main verb…
Before I could explain anything, he left
2) subject + main verb …/ subordinating conjunction + subject + verb …
He left before I could explain anything.
Tenses and aspects (simple, perfect, continuous) used:
1) After time subordinating conjunctions we use present tenses to refer to the future. In the main clause we typically use a future or imperative form:
When you are in town, visit me.