53.→We have looked for a flat for 2 months.
54.→I haven't been to a night club before.
55.→This is the first time,they have heard such a thing.
56.→This is the first time,everybody/everyone has challenged his authority.
57.→It's 2 years since she left University.
@TriLeCongTri
chúc em học tốt!!!!!!!!