$\text{52.}$ We have been looking for a flat for 2 months.

$\text{→}$ Tìm ở QK và vẫn đang tìm ở HT ⇒ chia HTHTTD

$\text{53.}$ I haven't been to a night club before.

$\text{→}$ This is the first time + HTHT<khẳng định> = HTHT<phủ định> + before

$\text{54.}$ This is the first time I have heard such a thing.

$\text{→}$ HTHT<phủ định> = have/ has + never + PP

$\text{55.}$ This is the first time someone has challenged his authority.

$\text{56.}$ It is 2 years since she left university.

$\text{→}$ It is + time + since + HTHT<khẳng định> = QKD<khẳng định> + time + ago

$\text{57.}$ I have never known such a warm-hearted person like my mother.

$\text{58.}$ It is over a year since I was last able to see them.

$\text{→}$ be able to-V: có thể làm gì

$\text{59.}$ It has been raining since 2 o'clock.

$\text{60.}$ It is the first time I have been to the ballet.

$\text{61.}$ It is 20 years since John and Mary moved to Edinburgh.

$\text{62.}$ For 2 months now, the police have been looking for him.

52.
 We have been looking for a flat for 2 months.

→
 Tìm ở QK và vẫn đang tìm ở HT ⇒ chia HTHTTD

53.
 I haven't been to a night club before.

→
 This is the first time + HTHT<khẳng định> = HTHT<phủ định> + before

54.
 This is the first time I have heard such a thing.

→
 HTHT<phủ định> = have/ has + never + PP

55.
 This is the first time someone has challenged his authority.

56.
 It is 2 years since she left university.

→
 It is + time + since + HTHT<khẳng định> = QKD<khẳng định> + time + ago

57.
 I have never known such a warm-hearted person like my mother.

58.
 It is over a year since I was last able to see them.

→
 be able to-V: có thể làm gì

59.
 It has been raining since 2 o'clock.

60.
 It is the first time I have been to the ballet.

61.
 It is 20 years since John and Mary moved to Edinburgh.

62.
 For 2 months now, the police have been looking for him.