18. It (be) cold when we (leave) the house that day, and a light snow (fall) 19. I (not see) Daisy for ages. When I last (see) him, he (try) to find a job in London. 20. I (walk) along the street when suddenly I (hear) footsteps behind me. Somebody ( follow) me. I was frightened and I (start) to run.

$#AP$

18. was cold, left, was falling.

DHNB: when

`->` QKD

19. have not seen, saw, was trying.

DHNB: for

`->` HTHT

DHNB: when

`->` QKD

20. was walking, heard, was following, started.

DHNB: when

`->` QKD

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Quá khứ đơn:

S + were/was

Did + S + V-inf?

Thêm ed vào động từ nguyên thể. `=>` watch - watched.

Động từ bất quy tắc. `=>` go - went.

-----------

Hiện tại hoàn thành:

S + have/has + V_past participle.

Have/has + S + V_past participle?

Thêm ed sau động từ nguyên thể. `=>` watch - watched.

Động từ bất quy tắc. `=>` go - went - gone.