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

Let x be the sum of a and b.

设x为a加b之和。

《牛津词典》

If a = b and b = c it follows that a = c.

设a = b，b = c，则a = c。

《牛津词典》

The hepatitis B virus is found in blood and bodily fluids.

VOA: standard.2010.07.26

So between b e, and b, between n and o, magnesium and aluminum, and then phosphorous and sulfur, what we see here is that we're kind of going down, or quite specifically, we are going down.

比如从铍到硼，从氮到氧，从镁到铝，从磷到硫，我们在这些地方看到有点下降，或者可以明确地说，我们确实在下降。

麻省理工公开课 - 化学原理课程节选

b It's pretty simple zeroth law says that if a and b it doesn't exactly say that but it implies this.

它很简单，第零定律指出如果a和,这不是第零定律的原话,但其意义是这样的。

麻省理工公开课 - 热力学与动力学课程节选

Thus the year ended peacefully, and B was ready to begin his true work.

NEWYORKER: The Autobiography of J.G.B.

Another who was depressed and drinking heavily was low on vitamins D and B-12.

WSJ: Confusing Medical Ailments With Mental Illness

If A equals B and B equals C then A too must equal C.

FORBES: You Call It Inflation, I Call It Theft