单项选择题

It can be inferred from the last paragraph that scientists ______.

A．are puzzled by the mystery of forest pollution
B．feel relieved by the use of unleaded gasoline
C．still consider lead pollution a problem
D．lack sufficient means to combat lead pollution
<上一题 目录 下一题>
热门 试题

单项选择题
The study published in the journal Nature indicates that ______.
A．the Clean Air Act has not produced the desired results
B．lead deposits in arctic snow are on the increase
C．lead will stay in soil and snow longer than expected
D．the US is the major source of lead pollution in arctic snow
单项选择题
What is the author's main point in the first paragraph
A．The penny press was modeled on earlier papers.
B．The press in the nineteenth century reached only a small proportion of the population,
C．The penny press became an important way of disseminating information in the first half of the nineteenth century.
D．The penny press focused mainly on analysis of polities.
相关试题