I’m considering ______ my house ________.
It suddenly occurred to him ________ he had left his keys in the office.
It was a real race ________ time to get the project done. Luckily, we made it.
—How far can you run without stopping? —_________. I’ve never tried.
A serious study of physics is impossible ________ some knowledge of mathematics.
—I’m afraid you have the wrong number. —Sorry! ________.