Some hard-working students always keep a torch in their dormitories _____ there is a power failure.
Even if they are on sale, these refrigerators are equal in price to, if not more expensive than, _____ at the other store.
Evidence obtained from observation and experiment is often used to _____ a scientific theory.
Because of the strong sun Mrs. William’s new dining room curtains _____ from dark blue to gray within a year.
. I asked the tailor to make a small _____ to my trousers because they were too long.
It was necessary to _____ the factory building as the company was doing more and more business.