Bonsoir.
A)
1. is devient isn't (is not)
2. they've (they have) devient they haven't (have not)
3. can devient can't (cannot)
4. the store sells devient the store doesn't (does not) sell
5. gave devient didn't (did not) give
B)
1. Should she find a store with low end products ?
2. Does he live in Central Texas ?
3. Did she want her products to be high end and very expensive ?
4. Do they have bought a new business in Texas ?
5. Could he be a very successful business owner ?
Pour la B) 3. il n'y pas de "and" entre "high end" et "very expensive" mais ça fait bizarre de ne mettre qu'une virgule, donc à toi de voir.
Passe une bonne soirée :)