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

B: On counter three.

B：在第三号柜台。

youdao

Influenza a, B and c, three separate strains of the virus, cause the flu.

三种不同的流感病毒流感A型、流感B型和流感C型都能引起流感。

youdao

An A is worth four points, a B three points, a C two points and a D one point.

VOA: special.2009.03.05

So what we'll have here is a trigonal planar case, and you can see that we only have three electrons that are set for bonding, so we'll add three hydrogens, and for b h 3, we'll get a stable structure here.

让电子劲量远离的时候，不用考虑它,这个例子是平面三角形，你可以看到，只有3个电子可以成键。

麻省理工公开课 - 化学原理课程节选

Why do you need three doses of Hepatitis B?

为什么你需要三支重组乙肝疫苗呢

耶鲁公开课 - 生物医学工程探索课程节选

It cut the other portion of MBIA's business to "B-three, " which is junk status.

FORBES: Municipal Bonds

United secured top spot in group B with three fine finishes from the 29-year-old, who still harbours hopes of making England's 2010 World Cup squad.

BBC: Michael Owen hat-trick delights Sir Alex Ferguson

For example, when the B-1A program was restarted to produce the B-1B, the per unit cost of the B-1B was three-times higher than the B-1A. Importantly, the B-1B was a modification (albeit a significant one) of the A-model and a gap of just 18 months occurred in the production line.

CENTERFORSECURITYPOLICY: Center For Security Policy