He made _____ experiments to prove his theory, and the number _____ added up to 600.

___________lessons were not difficult.

It’s time _____ lunch.—OK. Let’s _____.

tin Luther King, Jr. put it, peace is not merely a distant goal that we seek, but a means ________ we arrive at that goal.

Once you have become ______to cigarette smoking oralcohol, it is hard to _______it even though you try hard.