"Is she wearing a t-shirt?"
Translation:هَل هِيَّ لابِسة تي شيرْت؟
In case this helps: in US English a t-shirt is more informal than a shirt. So English to Arabic for 'shirt" it should be قميص but for an informal t-shirt perhaps the English loan word is ok? According to Arabic vs Arabic A Dialect Sampler (p. 7) the MSA and most common dialect word for shirt is قميص. Apparently in Algeria, where the French colonized, they commonly use the French word tricot.