—Kathy and her sister are so alike.—I can’t tell one from ____.
_______ the days going on, the weather is becoming hotter and hotter.
We tried to ______ his doubts and let him tell the truth.
Advertisements are a good __________ sell products or services.
Violence (暴力) computer games may have a bad ____________ on children.
Mary is often heard ________ playing piano in the next room in the evening.