correct this simple sentence

I think the last one is pretty weird with "yesterday" at the end.

^Yeah. Only the first one is correct.

Thank you friends.

OlaTheNetsurfer^Yeah. Only the first one is correct.

Do you mean third one is incorrect? I am too keen to know about the third sentence; particularly about the comma that I placed after the yesterday.

The last sentence sounds strange to me too. If you look at the order of the sentence you can use "while" at first but semantically it sounds strange.

Thank you Doll.

But I am talking about third sentence where I put a comma after the "yesterday".

It seems correct to me but I am not good at punctuation. The clause between commas seems like an explanative sentence.

Yesterday I fell down is the real message.----> Yesterday, while I was climbing on a tree, I fell down. The underlined sentence is an explanative one. Maybe this form of sentence is incorrect in terms of punctuation but I just comment it like this.

Hi,

As a minor comment, the usual expression is 'climb a tree' instead of 'climb up a tree'.

Note also that you would normally say 'a tree', unless you were speaking of one specific and previously mentioned tree.

Finally, we often say 'fell' rather than 'fell down'.

Clive