Subordinating conjunctions are words which connect one or more clauses to form a sentence, for example "dass" (that), "obwohl" (although), "ob" (whether). They must be preceded by a comma, and they send verbs to the end of the sentence. For example, "weil" (because) is another subordinating conjunction: "Ich habe den Zug verpasst, weil ich nicht schnell genug laufen konnte."