Question

highlight the subordinating conjunction (\swabi\) in the sentence.
since it is dark already, santas little helper should be careful biking home.

Explanation:

Subordinating conjunctions (SWABI includes words like Since, When, After, Before, If, etc.) introduce subordinate clauses. In the sentence, "Since" introduces the subordinate clause "it is dark already" and connects it to the main clause. So "Since" is the subordinating conjunction here.

Answer:

Since