单项选择题

The main cause of pollution is ______.

A．the release of artificial or natural substances into the environment
B．the production of new industrial goods
C．increased amounts of a natural substance
D．our ever-increasing population

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热门试题

单项选择题

The release of oil from oil tankers into the sea is ______.

A．the only source of pollution
B．a kind of pollution caused by the release of natural substances
C．of worldwide consequence
D．most harmful to mankind

单项选择题

Digital divide is something ______.

A．getting worse because of the Internet
B．the rich countries are responsible for
C．the world must guard against
D．considered positive today