干法熄焦和湿法熄焦相比，可明显提高焦炭质量，M40可提高（）。A、3~5% B、5~

Which of the following statements best describes the limits of arbitrage in correcting market anomalies（）

A. When fundamentals indicate that a stock is overvalued or undervalued, trading based on this information will be immediately profitable.

B. Arbitrage is not always risk-less as was shown during the internet stock bubble of the 1990s, when traders were short a stock and had to cover their positions at a much higher takeover price.

C. There is no limitation to arbitrage in correcting market anomalies because it is a risk-less trading activity and once there is a mispricing it will be exploited to its fullest.

该患者腹痛发生的机制包括

A．溃疡及其周围组织的炎性病变使局部内感受器的敏感性降低

B．局部肌张力增高

C．胃酸对溃疡面的刺激

D．对胃酸刺激的痛阈降低

E．浆膜面受侵

在我国下列属于限制民事行为能力人的有（）。

A.18周岁以上的成年人

B.10周岁以上的未成年人

C.不满10周岁的未成年人

D.不能完全辨认自己行为的精神病人

E.不能辨认自己行为的精神病人

为什么常规火力发电厂热效率较低？

电力负荷的含义是什么？电力负荷按重要性分哪几级？各级电力负荷对供电电源有什么要求？