33. This cake was made by my mother yesterday

34. If Lan didn't have so much homework to do, she could go with us

35. The teacher asked me what aspect of learning English the students found most difficult

36. My friend has collected stamps since 2005

1. That house was built ( by him ) last year

2. Ba asked Lan if she wanted to have some cold drink

3. If I had a pencil, I could draw a picture

4. My elder brother has learned English for 3 years

33. My mother made this cake yesterday.

⇒ This cake was made by my mother yesterday

34. Lan can't go with us because she has so much homework to do.

⇒ If Lan didn't have so much homework to do, she could go with us

35. "What aspect of learning English do the students find most difficult?" The teacher asked me.

⇒ The teacher asked me what aspect of learning English the students found most difficult

36. My friend began to collect stamps in 2005.

⇒ My friend has collected stamps since 2005

x x x x x x x

1. He built that house last year.

⇒ That house was built ( by him ) last year

2. "Do you want to have some cold drink, Lan?" asked Ba

⇒ Ba asked Lan if she wanted to have some cold drink

3. Because I don't have a pencil, I can't draw a picture.

⇒ If I had a pencil, I could draw a picture

4. My elder brother began learning English 3 years ago

⇒ My elder brother has learned English for 3 years