单选题

单选题 What can be said about the report by the National Academy of Sciences?

A、 It is presented in an authoritative tone.
B、 It is based on an objective analysis.
C、 It provides an unbiased view on global warming.
D、 It contains provocative remarks to skeptics.

【正确答案】 C

【答案解析】

单选题 How much has the world temperature gone up in the past 100 years?

A、 By 1 degree.
B、 By 2 degrees.
C、 By 4 degrees.
D、 By 5 degrees.

【正确答案】 A

【答案解析】

单选题 What is the largest energy source in the US today?

A、 Nuclear energy.
B、 Coal.
C、 Oil.
D、 Natural gas.

【正确答案】 B

【答案解析】

单选题 What hinders the extensive use of renewable energy sources?

A、 Lack of advanced storing technology.
B、 A need for joint efforts of scientists.
C、 A shortage of practical support from the public.
D、 An unreliable market demand.

【正确答案】 A

【答案解析】