1. I heard that trucks can no longer travel on Grove Street.
A. Adverbial
B. Adjectival
C. Noun ( That is the subordinate conjuntion. )
2. Wrap that meat in foil before you put it in the freezer.
A. Adverbial ( it is an adverbial clause of time. BEFORE, modifies the other clause in the sentence)
B. Adjectival
C. Noun
3. Since I will have a test in Spanish, I went to the language lab.
A. Adverbial (this is also an adverbial clause of time, modified by the adverb SINCE)
B. Adjectival
C. Noun