13. “I’ve lost one of my socks.” You ____ it somewhere.” (A)could drop (B)would have been dropping (C)should have dropped (D)must have dropped

12. When children talk back, it can be very rude. If parents or teachers don’t do anything about that, it can become a bad habit. ____, rude kids often become rude adults. (A)Better yet (B)Nevertheless (C)What’s worse (D)On the contrary