Complete the student's dramatic diary entry about a boring class.

The professor's voice was incredibly soothing, _____ I accidentally fell asleep and drooled on my textbook.

The correct answer is so.

We use so to show the result or consequence of a situation. The soothing voice caused the result of falling asleep.

• If we used because, the sentence would mean the soothing voice happened as a result of falling asleep, which doesn't make sense!