I. WORDFORM:
1. There is a wider selection of clothes for you in this summer. (SELECT) (Adj + N)
2. We produced enough food to feed the village last year. (PRODUCE) (S + V)
3. Some products at this shop are very cheap. (PRODUCE) (some + Ns/UN)
4. He's the president of a large international organization. (ORGANIZE) (Adj + N)
5. We'll continue this discussion some other time. (DISCUSS) (this + N)
6. The owners of the small stores think the mall will take their business. (OWN) (the + N)

II. PRESENT PERFECT <-> PAST SIMPLE:
1. I have never stayed in such an expensive hotel before.
This is the first time I have stayed in such an expensive hotel.
2. I haven’t seen Miss Nga since she left for Japan.
I last saw Miss Nga when she left for Japan.
3. This is the first time we have seen such a strange animal.
We have not seen such a strange animal before.
4. When did he start to teach Korean?
How long has he taught Korean?
5. We started writing to each other eight years ago.
We have written to each other for eight years.
6. How long have you swum in this pool?
When written to each other for eight years.

Công thức:
HOW LONG + HAVE / HAS + S + V3/ED ...?
WHEN + DID + S + V1 ...?
HOW LONG IS IT + SINCE + S + V2/ED ...?

S + HAVE / HAS + NOT / NEVER + V3/ED... + BEFORE.
THIS / IT IS THE FIRST TIME + S + HAVE / HAS + V3/ED...

`I.`

$1$ `:` selection 

`-` Adj `+` N

`->` Selection ( n ) `:` Sự lựa chọn

$2$ `:` produced

`->` Thì QKĐ `-` DHNB `:` last year

`-` QKĐ `:` S `+` V2 / V`-`ed `+` O.

$3$ `:` production

`-` Some `+` N

`->` Production `:` Sự sản xuất

$4$ `:` organization

`-` Adj `+` N

`->` Organization ( n ) `:` Tổ chức

$5$ `:` discussion

`-` This `+` N

`->` Discussion `:` Thảo luận

$6$ `:` owner

`-` The `+` N

`->` Owner ( n ) `:` Chủ nhân

`II.`

$1)$  This is the first time I have stayed in such an expensive hotel.

`->` This is the first time `+` S `+` have / has `+` VpII `+` O.

$2)$  I last saw Miss Nga when she left for Japan.

Áp dụng công thức thì QKĐ `:`

`( + )` S `+` V2 / V`-`ed `+` O.

$3)$  We have not seen such a strange animal before.

Áp dụng công thức thì HTHT `:`

`( + )` S `+` have / has `+` VpII `+` O.

`->` Thì HTHT `-` DHNB `:` before 

$4)$  How long has he taught Korean ?

`->` How long `+` has / have `+` S `+` VpII `+` O ?

$5)$  We have written to each other for eight years.

Áp dụng công thức thì HTHT `:`

`( + )` S `+` have / has `+` VpII `+` O.

`=>` For `+` Khoảng thời gian

$6)$  When did you swim in this pool

Áp dụng công thức thì QKĐ `:`

`(  ?  )` ( Wh ) `+` did `+` S `+` V_inf `+` O ?