Two Questions

When I was a child, gentlemen used to raise their hats to female acquaitances on the street and I was taught to mind my Ps and Qs and to give up my seat for my elders and betters on the bus. now I am grown-up, no one either raises their hat to me or offers me a seat on a crowded bus.
(English Vocabulary in Use / advance.Cambridge Un. Press )

Q1- What does "to mind my Ps and Qs" mean?

Q2-Why has the author used Their instead pf his? "raises their hat"

Thanks in advance.
Regards

[Tdol]

Mind your Ps and Qs = have good manners, be polite
Raise your hat- a polite way of greeting someone

Originally Posted by tdol

Mind your Ps and Qs = have good manners, be polite
Raise your hat- a polite way of greeting someone

Thanks a lot for your kind answer
But my second quwstion about "Their" . Why has the author used Their instead of his?

[bmo]

Originally Posted by Ahmed88

But my second quwstion about "Their" . Why has the author used Their instead of his?

Ahmed88, is it because it is gentlemen not gentleman?

Originally Posted by bmo

Ahmed88, is it because it is gentlemen not gentleman?

"no one either raises their hat" ???
My question about their
Should not have been "his" as far as we have a singular subject and verb +s.
Regards

[bmo]

Sorry, I was looking at the wrong place.

[Francois]

Originally Posted by Ahmed88

"no one either raises their hat" ???
My question about their
Should not have been "his" as far as we have a singular subject and verb +s.
Regards

It's the usual way to avoid "his or her". One often use it, don't they?
However, one could argue that only men raise their hat, so the gender would be defined in this case. Maybe it is just natural to the author to use "they" with no one, in all cases.

FRC