奇怪

That's queer indeed!

That's only natural. / There's nothing strange about it.

The wonder is why he was absent.

singular/strange to say; strangely

unusual phenomena

strange/weird idea

eccentric clothing

freakish/odd behaviour

strange expression

It's really surprising that they should still be in the dark.

We all feel surprised at the manager's resignation.

The fact that he was caught is not to be wondered at.

I shouldn't wonder if he stayed there.