I. Complete the sentences using suggested words.

1.There/book/on/the table.

2.There/shoes/under/the chair.

3.There/not/TV/in/his room.

4.There/not/pens/on/my desk.

5.There/boy/behind/that tree.

6.There/girls/in front of/the house.

7.There/not/telephone/in/her office.

8.There/not/chairs/downstairs.

a) - Đặt câu có sử dụng dấu phẩy.

b)- Hãy nêu tác dụng của dấu phẩy trong câu.