单项选择题

According to Schlesinger, the United States is ______.

A．a melting pot
B．a nation with diverse cultures held together by the democratic process
C．a federation of ethnic and racial communities
D．a nation with various ethnic and racial groups

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热门试题

单项选择题

The horizons of science have expanded means that ______.

A．the horizon changes its size from year to year
B．science has developed more fields of endeavor
C．scientists have made great progress in studying the horizon
D．scientists can see further out into space

单项选择题

The example given in the passage illustrates how ______.

A．pure science operates independently of applied science
B．the applied scientist discovers the basic laws of nature
C．applied science defines all the areas in which basic research is done
D．applied science suggests problems for the basic scientist