Please complete the summary of paragraphs C and D below.

请完成下面 C 和 D 段的总结。

youdao

Three other types of airspace, Classes D, C and B, govern the vicinity of airports.

其他三种领空，D、C 和 B 类，管理着机场周围地区。

youdao

For each of them there are four choices marked A, B, C and D. You should decide on the best choice and mark the corresponding letter on Answer Sheet 2 with a single line through the centre.

每题都有对应标记的A、B、C和D四个选项，请选择最佳选项并在答题卡2的相应字母中间划横线。

youdao

One study found that older Americans do not get enough Vitamin C and required minerals.

VOA: special.2009.04.21

a You know that what will happen is that heat will flow from a to b from b to c and from a to c. That's common-sense.

你知道会发生的是热量从流向,从流向,以及从流向。

麻省理工公开课 - 热力学与动力学课程节选

So, the first thing we do is put two electrons between h and c, and then two electrons between c and n.

那么，我们先在氢和碳之间放两个电子，然后在碳和氮之间再放两个电子。

麻省理工公开课 - 化学原理课程节选

That, in turn, boosted understanding of hepatitis B and C and still other viruses.

FORBES: The Golden Age of Antiviral Drugs

Her microlivers are also being put to work in the fight against hepatitis C and malaria.

FORBES: Magazine Article

This will establish the value of vitamin C and E supplements in all pregnant women.

BBC: Vitamins may reduce pregnancy danger