________ to playing games recently，he is

接触网工区应以比较熟练的工人为骨干组成抢修组，组长由（）或安全技术题号一二三四成绩复核人成绩阅卷人等级不低于（）的人员担当，组内应明确分工，有准备材料工具的人员、防护人员、坐台联系人、网上作业人员和地面作业人员等。

用板波法探测薄钢板时，（）把荧光屏上的反射波区分出是内部缺陷还是表面缺陷。

A.能

B.不能

C.有时能

D.观察不到表面缺陷波

An investor owns a stock portfolio that closely follows the Standard & Poor’s 500 Index (S&P500). He purchases one S&P500 stock index put option. The investor’s position is now portfolio insurance with the following characteristics: Portfolio position: LONG S&P500 Portfolio purchase price:1427.21 Option position: LONG 1 put option Underlying asset:S&P 500 Index Exercise price : 1225 Premium :3 Expiration date : November If the expiration-day price of S&P500 were 1200, then the expiration-day profit/loss for the portfolio insurance would be:

A．

B．

C．

扫道岔冰雪或清擦道岔前，应预先向谁取得联系？

在进行软管外胶层磨耗性能试验时，试验的数量至少为（）个。