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【单选题】
深秋或寒冬，霜冻多出现在晴朗的夜晚，主要是 [ ]A.
太阳辐射强
B.
地面辐射增强
C.
夜晚大气逆辐射弱
D.
地面辐射弱，大气辐射强
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皮皮学刷刷变学霸
举一反三
【简答题】When cost externalities exist, an optimal equilibrium can be attained if the governmentA. restricts production. B. levies a tax for the difference between private costs and social costs. C. prohibits ...
【单选题】The Coase theorem states that, in the presence of cost externalities, an optimal equilibrium can be attained
A.
with government taxation.
B.
by prohibiting production.
C.
by correctly defining property rights and through negotiation between the parties.
D.
None of the above.
【多选题】下面哪些是防范SQL注入的手段___。
A.
安全编码规范（输入验证、遵循安全SQL编码规范）。
B.
代码审计、SQL注入测试等，可手工也可以结合自动工具。
C.
启用主机防火墙。
D.
数据库安全加固、Web应用防火墙、IDS/IPS
【单选题】If the point price elasticity of demand equals -2 and the marginal cost per unit is $5, the optimal price is:
A.
$5
B.
$10
C.
$2
D.
impossible to determine without further information.
【判断题】The optimal promotion mix is dependent on the cost of each promotional method.
A.
正确
B.
错误
【单选题】When the output is less than the optimal rate of output, the average unit cost will be:
A.
lower
B.
the same
C.
higher
D.
could be either higher or lower
E.
could be either higher, lower or the same
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