20.nien asked Hoa if she had many friends.
21.would you mind turning on the light?.
22.soccer is played in the world.
23.i have learnt E for 10 years.
24.would you mind playing soccer here?.
25.i've learnt E since I was 10 years old.
26.my book hasn't been returned by Mary yet.
27.it's difficult to find a job at my age.
28.it's easy to get acquainted with the regulation in a new school.
28.this letter isn't written by the principle.
29.it's harmful to smoke a lot.
30.a birthday cake is being made in the kitchen by Mary.
