做功和热传递对内能的改变是等效的，二者在本质上不存在差异
查看答案
系统经历绝热变化过程后，其内能的改变量为零。
A. 对
B. 错
绝热过程中系统对外做功全部以系统内能减少为代价的
A. 对
B. 错
Which of the following would be counted in the calculation of GDP?
A. the sale of a rare coin to a coin collector
B. homes that are rebuilt after being completely destroyed by a hurricane
C. the sale of a 1966 Ford Fairmont.
D. the sale of cocaine in the black market.
The largest component of GDP is
A. net exports.
B. consumption.
C. government purchases.
D. investment.
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