A But I tend to use P Q R for sentences and A for A, now that I have explained it, that should be smaller case.

但是我喜欢用P，Q，R来代表句子，A就代表，我已经解释了，应该是小写的。

youdao

We want to know whether a given vector field with components P, Q and R can be written as f sub x, f sub y and f sub z for a same function f.

要看向量场,能否写成，其中f是同一个函数。

youdao

The common resource constraint for inventory systems is a linear resource constraint which may result in high operating costs in multi-item (r, Q) inventory systems.

库存系统常见的资源约束形式是线性资源约束，但应用于多品种(R, Q)库存系统时会带来较高的运作成本。

youdao

Mr. Davis was taken into custody on Tuesday just a block away from the 49th Street N Q R station.

WSJ: New York Subway Push: Murder Charge for Suspect Naeem Davis

In 2010, a cook was convicted of assault after pushing a woman into the side of a moving subway car at the 28th Street and Broadway station, which serves the Q, N and R trains.

WSJ: Man Dies After Push Onto Track