There is _____ pollution in the world. W

在某个网络上的两台服务器之间需要传输1.5小时的文件，而该网络可能每隔0.5小时崩溃一次。这时可以考虑在数据流中加入一个校验点，使得在网络崩溃后，只是最后一个校验点之后的数据进行重传。在OSI参考模型中，这个校验点最有可能是由（）完成的。

A．数据链路层

B．传输层

C．会话层

D．应用层

如图所示，患者发热、胸痛2个月，最可能的诊断是（）

A.肺癌

B.肺炎

C.转移癌

D.肺动脉栓塞

E.真菌感染

关于执法部门履行下列职责，有哪些说法是正确的（）

A.执法部门依照环境保护管理方面法律、法规、规章的规定，对违反环境保护管理规定的部分行为实施行政处罚

B.执法部门依照市政公用管理方面法律、法规、规章的规定，对违反市政公用管理规定的行为实施行政处罚

C.执法部门依照工商行政管理方面法律、法规、规章的规定，对在城市道路、广场等室外公共场所无照经营的行为实施行政处罚

D.执法部门依照城乡规划管理方面法律、法规、规章的规定，对违反城市绿化管理规定的部分行为实施行政处罚

With 22 years on the job, Jackie Bracey could be considered a career employee of the Internal Revenue Service. But she defies any stereotype of an over-eager agent running down a reluctant taxpayer. Instead, she spends her time defending people who owe the government money. Ms. Bracey, based in Greensboro N. C., is a taxpayer advocate, a created by Congress in 1998 as part of the kinder, gentler theme adopted by the tax collection agency. Bracey and advocates at 73 Other offices nationwide, backed by 2,100 field workers and staff, go to bat for taxpayers who are in financial straits because of something the agency has done or is about to do.

Though it may seem contrary to the IRS, the advocate service not only helps taxpayers, but identifies procedural problems. The main goal, though, is for the ombudsman to step into a dispute a taxpayer is having with the IRS when it appears that something the IRS is doing, or planning, would create an undue hardship on the taxpayer. This can range from speeding up resolution of a dispute that has dragged on too long, to demanding that the IRS halt a collection action that the taxpayer can show he or she “is suffering or is about to suffer a significant hardship.”

Taxpayer ombudsmen have been around in one form or another since 1979, says Nina Olson, the national taxpayer advocate. But they were given much more power in 1998 when Congress decided that the workers would no longer report to regional directors but to her office. While this gave them a great deal more authority, outside watchdogs say more can be done. “There is a long way to go to get an agency that feels independent and emboldened to work for taxpayers”, says Joe Seep, a vice president of the Washington-based tax-advocacy group.

The taxpayers union also has complained that Congress and the Bush administration don’t seem to be taking the advocates seriously enough. Each year, the IRS group reports to Congress on the top problems that advocates see. Many of these are systemic problems that can gum up the works for both taxpayer and collector, such as a December notice from Ms. Olson that the IRS should have just one definition of a dependent child, rather than the three definitions currently used. While taxpayer advocates can help smooth things out in many cases, they cannot ignore laws.

If taxpayers haven’t made legitimate claims for credits, there’s nothing the advocate can do to reverse that course. And Olson says that while taxpayers are free to use her service, they should keep in mind that it does not replace the normal appeals process and should be the last place a citizen calls upon for help, not the first. “We’re really there for .when the processes fall down,” she says. Every state has at least one taxpayer-advocate service office.

The phrase “gum up the works” (Line 3, Para. 4) probably mean（）

A.to impair the benefits

B.to bring about solutions

C.to lead to trouble

D. to improve the relations