On the flight to Chongqing, the memory of my childhood, _______ I was my father’s shadow, came flooding back.
In much of the animal world, night is the timefor sleep-pure and simple.
Butterflies ______ a sweet liquid produced by flowers, which bees and other insects collect.
According to the law, all foreigners have to ______ with the local police within two weeks of arrival.
While intelligent people can often ______ the complex, a fool is more likely to complicate the simple.
Carbon dioxide, which makes a ______ between us and the sun, prevents heat from getting out of the atmosphere easily, so the earth is becoming warmer.