I wonder that/ I wonder if grammar and usage

[Jeonghee]

1. I wonder that somebody came.
2. I wonder if somebody came.

Is No. 2 a proper sentence and How much can it be used among people?

 

[emsr2d2]

1. I wonder that somebody came.
2. I wonder if somebody came.

Is [STRIKE]No. 2 a proper[/STRIKE] sentence #2 correct and how much can it be used among people?

Please note my changes and underlining above. I don't know what you mean by the underlined part. Are you asking us how common sentence #2 is?

Sentence #1 is an old-fashioned way of saying "I am surprised that somebody came".
Sentence #2 is grammatically OK but not very natural. I would expect to see "I wonder if anybody came". That would be used of an event or a situation that I didn't attend and I am wondering if anyone else actually turned up.

 

[Tarheel]

There wouldn't be much occasion to use either one, so I wouldn't worry about how they are used.