一般水工建筑物裂缝及分缝止水破坏的原因是什么？

At a recent seminar on Capital Market Efficiency, David Thorngate, a seasoned arbitrageur wanted to dispel the notion that all arbitrage trades are successful. During his speech, he made the following statements regarding arbitrage and the ability of arbitrageurs to correct market anomalies: Statement 1: There are limits on the ability of arbitrage to bring about efficient prices. Arbitrage is frequently not risk-less. Just because fundamentals indicate that one stock is undervalued or overvalued relative to another does not mean that trading on this information will be profitable. Statement 2: Even in "pairs trading," where an arbitrageur buys the underpriced security and shorts the overpriced security, significant risk from stock-specific factors remains. So, there is no guarantee that even correctly identified relative mispricings of similar stocks will be corrected in the near term. Are Statement 1 and Statement 2 as made by Thorngate correctStatement 1 Statement 2（）①A. CorrectCorrect ②B. Incorrect Incorrect ③C. CorrectIncorrect

A. ①

B. ②

C. ③

股静脉、股动脉穿刺术

特定化学形式物质的放射性活度占总放射性活度的比例，称为（）

A.放射性比度

B.放射性核纯度

C.放射性化学纯度

D.化学纯度

E.放射性浓度

工程中，压力的国际单位是（）。

A、N

B、kg

C、Pa

D、1b

代表方剂为

A．身痛逐瘀汤

B．左归丸

C．右归丸

D．甘姜苓术汤

E．四妙丸