—Kathy and her sister are so alike.—I can’t tell one from ____.
In ______ eyes of my parents, a knowledge of English is ______ must in the world today.
--Spacecraft "Discovery" has failed in the course of launch.--_____? They have been preparing for the test.
Every time_____they met, they would talk several hours together about all of the situations_____ appear in the working world.
It_____we had stayed together for several weeks_____ I found we had a lot in common.
You_____ all those calculations! We have a computer to do that sort of thing.