Clauses of time with "bevor", "bis", "seit(dem)", "sobald", "solange" 

Clauses of time are subordinate clauses. The verb is placed at the end of the subordinate clause.
B E V O R
(before)
The subordinate clause indicates what happens chronologically after the action of the main clause.
Bevor Nina abends einschläft, liest sie ein Buch.
B I S
(until, till)
The subordinate clause indicates what happens chronologically
after the action of the main clause. The focus is on the end of the action.
Bis ich mir das neue Handy kaufen kann, muss ich noch drei Monate sparen.
S E I T (D E M)
(since)
The subordinate clause indicates the beginning of a period of time.
Seitdem ich in Hamburg wohne, habe ich viele neue Freunde gefunden.
S O B A L D
(as soon as, once)
The subordinate clause indicates what happens chronologically
before the action of the main clause.
Sobald wir in Frankfurt gelandet sind, rufen wir dich an.
S O L A N G E
(as long as, while)
The actions of main clause and subordinate clause happen simultaneously.
The joint end of the two actions is important.
Solange die Temperaturen so hoch bleiben, gehen wir jeden Tag ins Freibad.