Bị động:

- HTHT: S + has/have + been + V3/ed 

- QKD: S + was/were + V3/ed 

- HTD: S + am/is/are + V3/ed 

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EX2: 

1. has been used 

DHNB: for two years (HTHT)

2. was discovered 

3. has been widened 

DHNB: since 1999 (HTHT)

4. was finished 

DHNB: in 1973 (QKD)

5. is situated 

6. was built 

DHNB: ago (QKD)

7. were visited

DHBN: last week (QKD)

8. was completed

DHNB: in 1937 (QKD)

9. was formed 

DHNB: 1209 (QKD)

10. was opened

DHNB: in 2010 (QKD) 

EX3: 

1. Exercises are often done every night.

2. The room is usually decorated at weekends. 

3. Country songs are always sung by Daisy.

4. Her sister is often given sweets.

5. These trees are often watered by Nam and Peter.

`color{orange}{~MiaMB~}`