压力容器投运前应做好各项准备工作，符合要求后方可投运。

气管开放性损伤可出现()

A．咳嗽及咯血、呼吸困难、气肿、局部疼痛

B．疼痛、吐血或呕血、气肿

C．颈部血肿、神经受压、脑缺血等

D．空气逸出、刺激性咳嗽、呼吸困难

E．吞咽痛、吐血、呕血、皮下气肿、颈部可见食物及唾液溢出

接收和阅读邮件，与他人进行电子通信的基础任务不包括（）。

A.删除邮件

B.阅读邮件

C.查看邮件附件

D.保存邮件附件

Scientists now believe that artificial-hip implants, previously thought to be safe, may actually increase the risk of cancer in recipients after about 45 years of use. Though these implants do improve the quality of recipients’ lives, the increased risk of cancer is an unacceptable price to pay for these improvements. Therefore, they should be banned.
Which of the following, if true, is the pest counterargument to the argument above

A．Artificial-hip implant surgery can cause severe complications, such as infection, chronic fever, and bone degeneration, and these complications can themselves be crippling or even fatal.

B．Almost all artificial-hip implant recipients receive their implants at an age when they are unlikely to live more than an additional 30 years.

C．Although artificial-hip implants increase the risk of cancer after about 45 years of use, a few of the cancers they induce are not fatal.

D．Since artificial-hip implants are not very common, banning them would cause little hardship.

E．(E) Although the benefits of artificial-hip implant surgery have remained substantially the same over the past decade, the price of the surgery has risen considerably.

在常规投资项目中，只要累计净现金流量大于零，则其内部收益率方程有唯一解，此解就是项目的内部收益率。 ( )

进气道安装有（）。

A.防冰系统；

B.内话地面插孔及T12探头；

C.A+B。