Translation:Ele gosta desta camisa porque é azul.
This exact sentence came up 5 times so far in this lesson...
He really likes his blue shirt.
How do they figure it is "desta" not "deste or este/esta?"
Because camisa is feminine. Desta camisa/ deste vestido
Should pois work here in place of porque?
Yes but is less common in spoken discourse.
Why is it wrong to omit the pronoun in this sentence?
Why can't I write "esta" instead of desta?
You should use "de" after gostar. De + esta = desta.