To be able to 

Tig liom            - I can

Tig leat             - you can

Tig leis         - he can, it can

Tig léi            - she can it can

Tig linn           - we can

Tig libh           - ye can

Tig leof'            - they can

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Possiblities 

Féidir           – it is possible (that)

B'fhéidir              - maybe

in ann           - able to

an chaoi             - the means of, the ability to

in aon turas             - for the purpose of

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To not be able to 

a'fearacht           - dithering

Mura féidir a dhéanamh ar a gcaoi seo, b'fhéidir go féidir a dhéanamh ar chaoi eicínt eile          - If it can't be done this way, maybe it's possible to do it some other way

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