1.The varsity team will play as soon as the junior varsity is finished.

2.Thirty laps is the most that I have ever swum.
3.My sister was going to take me to dinner, but her car wouldn't start.

Identify each independent clause in each sentence and each subordinate clause. Then tell if the sentence is simple, compound, complex, or compound-complex

1.simple
2.simple
3.My sister was going to take me dinner=independent clause
her car wouldn't start=independent clause
compound sentence

2 answers

Still not real sure after looking at the web-sites.
You are right about #3.

For #1 --
The varsity team will play = ind cl
as soon as the junior varsity is finished = dep cl

For #2 --
Thirty laps is the most = ind cl
that I have ever swum = dep cl

Note the existence of an introductory (signal) word/phrase at the beginning of both dependent clauses: "as soon as" and "that."
http://grammar.ccc.commnet.edu/grammar/clauses.htm#dependent