He took off his clothes and （lie)down to sleep.
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The little boy (not watch )TV every day.
在当前的云计算领域，Google的（）和Hadoop开发的开源系统（）是比较流行的两种云计算分布式存储系统。（填英文缩写）
MapReduce模式将任务自动分成多个子任务，通过Map和Reduce两步，实现任务在大规模计算节点中的调度与分配。
A. 对
B. 错
[单选]One way in which monopolistic competition differs from oligopoly is that
A. there are no barriers to entry in oligopolies.
B. in oligopoly markets there are only a few sellers.
C. all firms in an oligopoly eventually earn zero economic profits.
D. strategic interactions between firms are rare in oligopolies.
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