Exercise 1: Read and decide the sentences "compound or complex" sentences.

Đáp án:

1. Compound (I like to play soccer, and my sister prefers basketball.)
2. Complex (After the rain stopped, we went for a walk in the park.)
3. Complex (She sings beautifully, but she never performs in public.)
4. Complex (Because it was getting late, we decided to call it a night.)
5. Complex (Jack loves reading books, yet he rarely finds time for it.)
6. Complex (Although it was cold outside, they still went swimming in the lake.)
7. Complex (Peter wanted to buy a new car, but he couldn't afford it.)
8. Complex (Sara studied hard for the exam, which is why she passed with flying colors.)
9. Complex (He enjoyed the movie so much that he watched it twice.)

Exercise 2: Combine the sentences and decide if they are compound or complex sentences.

Đáp án:

1. Complex: The air is polluted because factories release harmful gases.
2. Complex: The water in the river is polluted so fish cannot live in it.
3. Complex: Mary wants to help the environment so she participates in beach clean-ups.
4. Complex: The city is experiencing an increase in pollution so the government needs to take action.
5. Complex: We should reduce plastic usage because it will help reduce pollution.
6. Complex: Many people use cars for transportation and cars emit harmful exhaust fumes.
7. Complex: The ozone layer is damaged so ultraviolet rays cause harm to living beings.
8. Complex: Recycling is important because it helps to reduce waste.
9. Complex: The burning of fossil fuels is common and it leads to an increase in greenhouse gases.