如图,ab为一公路,cd为一河流,A、B分别为小村庄.读图回答.
A. It's time for Chinese class. B. It's time for lunch.
C. It's time for school. D. Time to go home.
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如图所示是某同学制成的“自动给水装置”,它是用一个装满水的塑料瓶子倒放在盆中,瓶口刚好被水浸没,其瓶中水面能高于盆内水面,主要是由于 ( )