单项选择题

In the author's opinion ,point-source pollution is ______.

A．less difficult to control than non-point pollution
B．the minor pollution source
C．more difficult to control than non-point pollution
D．a problem that cannot be solved

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单项选择题

According to the author, Kids' Country is partially caused by ______.

A．development
B．immigration
C．inheritance
D．wealth

单项选择题

It is implied in the passage that ______.

A．water pollution is the most serious one in all kinds of pollution
B．both point-source and non-point pollution are serious problems
C．point-source pollution is an unimportant problem
D．water pollution can only be controlled by the law