—Kathy and her sister are so alike.—I can’t tell one from ____.
Nuclear science should be developed to benefit the people _____ harm them.
It is a great pleasure for a woman to ________ the price while shopping.
. ______ the ancient Egyptians built the pyramids puzzled people for centuries.
No one but the experts in this field can _____ the difference between them.
—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.