I wonder if it could be the same one I heard of when my father was drowned?

我想知道，是不是我爸爸淹死时我听说的那条？

youdao

I wonder if it is the key to the garden.

我想知道这是不是花园的钥匙。

youdao

I wonder if it is really that funny.

我不知道，它是不是真的那么可笑。

youdao

I also wonder whether if it's a good way of focusing the world's attention on the issue of blood diamonds and on this very important trial by getting such a high-profile figure involved with it."

VOA: standard.2010.08.05

When I look at the car in 2010 and say there's a car I wonder if it's the same car.

当我看到2010的车0,说这有辆车,我想知道是不是我那辆。

耶鲁公开课 - 死亡课程节选

The "I wonder if" pattern, like it sounds, is used to express the fact that you don't completely know something.

I wonder if”句型，就像字面意思表达的一样，是用来表达你对某事并没有彻底的了解。

I wonder if 课堂 - SpeakingMax英语口语达人

You wonder if it's going to work any better for him.

NPR: Democrats Feud; McCain Stews over 'Times' Piece

You will wonder if it's because you are not good enough.

BBC: Q&A: Chinese dating consultant Zhou Xiaopeng

You never wonder if it's going to be able to thread itself into moving traffic or attain highway speed before a truck looms up behind you.

WSJ: 2012 Toyota Prius c Review: Pleasure Not Included | Rumble Seat by Dan Neil