黄金市场的参与主体有哪些？

活血化瘀药丹参的主要药理作用是（）。

A.抗病原体

B.抑制免疫功能

C.调解肠胃功能

D.调解神经功能

E.改善血液流变学特性

以下为水密装置的是（）

Ⅰ．水密舱壁上开口的关闭设备；Ⅱ．船壳板上开口的关闭设备；Ⅲ．舱壁甲板以上的水密装置。

A.Ⅰ，Ⅱ

B.Ⅰ，Ⅲ

C.Ⅱ，Ⅲ

D.Ⅰ～Ⅲ

在圆弧顶或圆弧底形态形成过程中，成交量的变化都是两头少，中间多。( )

Despite increased airport security since September 11th, 2001, the technology to scan both passengers and baggage for weapons and bombs remains largely unchanged. Travellers walk through metal detectors and carry-on bags pass through x-ray machines that superimpose colour-coded highlights, but do little else. Checked-in luggage is screened by "computed tomography", which peers inside a suitcase rather like a CAT scan of a brain. These systems can alert an operator to something suspicious, but they cannot tell what it is.

More sophisticated screening technologies are emerging, albeit slowly. There are three main approaches: enhanced x-rays to spot hidden objects, sensor technology to sniff dangerous chemicals, and radio frequencies that can identify liquids and solids.

A number of manufacturers are using "reflective" or "backscatter" x-rays that can be calibrated to see objects through clothing. They can spot things that a metal detector may not, such as a ceramic knife or plastic explosives. But some people think they can reveal too much. In America, civil-liberties groups have stalled the introduction of such equipment, arguing that it is too intrusive. To protect travellers ’modesty, filters have been created to blur genital areas.

Machines that can detect minute traces of explosive are also being tested. Passengers walk through a machine that blows a burst of air, intended to dislodge molecules of substances on a person’s body and clothes. The air is sucked into a filter, which instantaneously analyses it to see whether it includes any suspect substances. The process can work for baggage as well. It is a vast improvement on today’s method, whereby carry-on items are occasionally swabbed and screened for traces of explosives. Because this is a manual operation, only a small share of bags are examined this way.

The most radical of the new approaches uses "quadrupole resonance technology". This involves bombarding an object with radio waves. By reading the returning signals, the machines can identify the molecular structure of the materials it contains. Since every compound—solid, liquid or gas—creates a unique frequency, it can be read like a fingerprint. The system can be used to look for drugs as well as explosives.

For these technologies to make the jump from development labs and small trials to full deployment at airports they must be available at a price that airports are prepared to pay. They must also be easy to use, take up little space and provide quick results, says Chris Yates, a security expert with Jane’s Airport Review. Norman Shanks, an airport security expert, says adding the new technologies costs around $100,000 per machine; he expects the systems to be rolled out commercially over the next 12 months. They might close off one route to destroying an airliner, but a cruel certainty is that terrorists will try to find others.

What is the relationship between the 2nd paragraph and the 3rd, 4th and 5th paragraphs（）

A. A generalization is made in paragraph 2 and then elaborated in paragraph 3,4 and 5

B. More sophisticated screening technologies are mentioned in paragraph 2 and 3 and then examples are provided in paragraph 4 and 5

C. Specific evidence is provided in paragraph 1, 2 and 3 and then a conclusion is drawn in paragraph 4

D. Three main approaches are advanced in paragraph 2,3 and then their functions are detailed in paragraph 4 and 5

至阳位于（）

A.第4腰椎棘突下

B.第2腰椎棘突下

C.第1腰椎棘突上

D.第10胸椎棘突下

E.第7胸椎棘突下