~というもの (the thing called)

A fighter who's trained hard for decades can be felled by a weak one in just a moment's carelessness. That's what the world of martial arts is.

...There's plenty I'd like to say, but butting in here would be tacky.

Much later, when I was studying philosophy of science, I learned that experiments should arise from real dissatisfaction with existing knowledge.

When I was six, I was taken to something called a circus for the first time.

For the first time, I was taken to what's called a 'circus.'

A good son always wants to please his parents.

There are limits to everything.