Which sentence contains an adverb clause?

A. Does the boy whose kite we borrowed live in the cottage across the street?

B. Before we left the camping grounds, we noticed a sign for the scenic trail.

C. The stuffed plush bear that Randall bought for his baby brother is soft.

D. That bracelet, which is made of sterling silver, has a delicate clasp.

Question

Which sentence contains an adverb clause?	
 
 A. Does the boy whose kite we borrowed live in the cottage across the street?
 
 B. Before we left the camping grounds, we noticed a sign for the scenic trail.
 
 C. The stuffed plush bear that Randall bought for his baby brother is soft.
 
 D. That bracelet, which is made of sterling silver, has a delicate clasp.

anonymous · Answer

Adverb clause: has subject and verb but acts like an adverb.
Adverb: modifies verb, adjective, adverb.

"Before we left the camping grounds" tells when they noticed.