He managed to reach the summit of his career, but it was at the _________ of his health.

There ___ no water in the well.

—Who did you stay with yesterday? I couldn’t find you anywhere.— ___________. 

—He was downloading reading materials from a website when the computer crashed.—_______ that he looked a little upset.

The lack of eco-friendly habits among the public is thought to be a major _____of global climate change.