8.The most crucial problem any economic system faces is how to use its scarce resources.
A） puzzling
B） difficult
C） terrifying
D） urgent
9.Human facial expressions differ from those of animals in the degree to which they can be deliberately controlled and modified.
A） sufficiently
B） noticeably
C） intentionally
D） absolutely
10.The Constitutions vague nature has given it the flexibility to be adapted when circumstances change.
A） imprecise
B） concise
C） unpolished
D） elementary
11.The expedition reached the summit at 10:30 that morning.
A） top of the mountain
B） bottom of that morning
C） starting point
D） site
12.The latest census is encouraging.
A） count
B） statement
C） agreement
D） estimate
13.Academic records from other institutions often become part of a universitys official file and can neither be returned to a student nor duplicated.
A） borrowed
B） purchased
C） copied
D） rewritten
14.While serving in the Senate in the early 1970s Barbara Jordan supported legislation to ban discrimination and to deal with environment problems.
A） list
B） forbid
C） handle
D） investigate
15.Gambling is lawful in Nevada.
A） legal
B） irresistible
C） enjoyable
D） profitable