Fòram na Gàidhlig

Sin agad e.

Are you asking what form you should use? Just stick to the full versions (mu mo, mu ar...) As long as you recognize what the other forms mean when you see them, it's all good. Are you worried about hearing these contractions in fast speech? As your listening skills increase, a helpful clue is to lis...

Tha sin ceart.

Seo agad earrann bhuntainneach a tharraing mi às an leabhar aig Raghnall MacilleDhuibh, "Cothrom Ionnsachaidh".

Yep, that's correct.

Here's a relevant excerpt I took from Ronald Black's book Cothrom Ionnsachaidh:

"Feumaidh tu mo thoirt..." - Seo an dòigh àbhaisteach ann an Gàidhlig na h-Alba. Riochdair sealbhach a chleachdadh airson a' chuspair dhìrich. Air uairibh cleachdar an dòigh eile le riochdairean làidir: "Feumaidh tu mise a thoirt air falbh." "Feumaidh tu mi/mise a thoirt...&...