We encounter similar difficulties when we substitute rectangles for triangles in this configuration.

Not at all, that's perfectly fine. Calling each other by one's given name is a good thing; it produces a feeling of fellowship.

Our yacht club has ten members.

Animals have bodies largely composed of fluid.

Water consists of hydrogen and oxygen.

Each party shall consist of not less than fifteen people.

The committee is composed of three men and seven women.

Child-care leave and time off to care for the aged are needed in order to respond to demographic changes now taking place in Japan.

I don't care what he does.

I don't care what people think about the way I dress.

In short some guns have excellent security systems to prevent accidental firing (e.g. when dropped), others don't.

This sees English as a system obeying miles of grammar and sentence structure which have to be learned in detail and applied rigorously.

That decision, in turn, was affected by the geological structure of the hill itself.

Some Japanese wives are content to leave their husbands alone.

My father does not care about his clothes at all.