Select the word that the adverb clause modifies in this sentence. our family worked on a 5,000-piece jigsaw puzzle because we wanted a fun challenge.

The word that is modified by the adverb clause is worked. This adverb clause is functioning as an adverb, modifying the verb. This subordintate clause is telling us the reason why "Our family worked..."The adverb clause is a subordinate clause that is joined to the main clause by the subordinating conjunction because.

a.) it provides a clue to solve the mystery.

1.the hosts on two opposing mountains stood,  

2.thick as the foliage of the waving wood;  

3.between them an extensive valley lay,  

4.o'er which the gleaming armour pour'd the day,  

5.when from the camp of the philistine foes,

6. dreadful to view, a mighty warrior rose; in the dire deeds of bleeding battle skill'd,