The formal diplomatic relations between China and the United States were established on（）

单项选择题According to the census prediction, the average male Americans will be expected to live up to （） years of age by 2050.

A．73.3
B．75.1
C．81.3
D．83.6

单项选择题Crime experts predict that in the near future crime rates will first decrease in（）

A．South and Southwest.
B．North and Northeast.
C．Southwest and Midwest.
D．Northeast and Midwest.

单项选择题The passage is primarily （）in the development of the thesis.

A．persuasive
B．descriptive
C．narrative
D．expository

单项选择题The following passage emphasizes the role of （） in health conservation.

A．advertising
B．research
C．governments
D．taxation

单项选择题The writer of the passage mainly intends to（）

A．criticize Germany's tax system.
B．help companies ease their tax burden.
C．examine the current corporate tax rates.
D．propose ways to reform the tax system.