Exercise 2: Trong số những câu sau đây, có những câu chứa một lỗi sai và có những câu chính xác. Nếu câu đó đúng, bỏ qua, nếu câu đó sai, hãy tìm và sửa lỗi sai. 1. The president, surrounded by secret service agents, is trying to make his way to the podium. 2. The buildings is destroyed during the fire are being rebuilt at the taxpayers’ expense. 3. 20 percent of the forest has been destroyed lately. 4. The witnesses saw that most of the fire in the hills was extinguished. 5. Some of the animals from the zoo was released into the animals preserve. 6. All of the students in the class taught by Professor Roberts is required to turn in their term papers next Monday. 7. Half of the food that we are serving to the guests is still in the refrigerator. 8. We believe that some of the employees is going to get promoted soon. 9. The people in the apartment next to mine are giving a party this evening. 10. Each of the doctors in the building need to have a separate reception area. ( mn giúp e bài này vs, khó quá đi , cảm ơn ạ)