1. "They are doing an experiment"

⇒ He said that they were doing an experiment

2. "You have to sign the paper again"

⇒ She told me to sign the paper again

3. Acid rain is dangerous. Trees' leaves are damaged( because of)

⇒ Because of the acid rain, trees' leaves are damaged

4. They built this house yesterday

⇒ This house was built yesterday

Question I Rewrite the sentences so that it has similar meaning to the first.

1. He said that they were doing an experiment. ( câu tường thuật nên phải lùi thì từ hiện tại tiếp diễn sang quá khứ tiếp diễn )

2. She told me that I had to sign the paper again. ( nt )

3. Because of the dangerous acid rain, trees'leaves are damaged. ( because of+N)

4. This house was built yesterday. ( câu bị động của thì quá khứ đơn )