拉伸试验可得岀哪些力学性能指标？工程上这些指标是怎样定义的？
According to the author, what should public policy aim at in the years to come？
A. Encouraging healthy economic growth.
B. Avoiding inflationary pressures.
C. Reducing inflation.
D. Striking a balance between A and B.
The authors attitude toward the decline of the U. S. balance of payments deficit can be summarized as______.
A. depressed
B. optimistic
C. objective
D. impartial
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