Question

13. Studying English is necessary these days.

-> It's ..............................................................

14. Do you mind if I sit here?

-> Would you mind if I .....................................

15. Could you turn down the gas fire?

-> Would you mind .............................................

Answer 1

13 necessary to study English these days.

14 sat here?

15  turning down the gas  fire?

Answer 2

13. It's necessary to study English these days

14. Would you mind if I sat here?

15. Would you mind turning down the gas fire?