I w' like to know, when do i use that and which?
I have a dubiety about sentences composition.
There have been many previous discussions on this forum on this subject. If type "that or which" into the Custom Search box, you will be able to read all our previous threads.
If you had given your post a relevant title, those Similar Threads would have shown up automatically. "My" is not a relevant title for the thread. A better title would have been "that or which".
Please note my corrections to your post above in red. I don't know why you wrote a "w" followed by an apostrophe instead of the word "would". There is no contraction for the word "would". You can shorten "I would" to "I'd" but at your level of English, I recommend that you write all words in full.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.