Chuyển câu sang số nhiều: 1. This is amchair; 2. I am a student; 3. It is a couch; 4. What is this? It's a stereo; 5. What is that? It's a bookshelf

Câu 1. Viết dạng số nhiều của những danh từ sau 
armchair, table, lamp, bag, couch, knife, family 
house, eraser, window, stereo, class, play 
Câu 2. Chuyển các câu sau sang số nhiều 
This is amchair 
I am a student 
It is a couch
What is this ?  It's a stereo
What is that ? It's a bookshelf
That is an eraser 
Câu 3. Đọc về gia đình Nam và trả lời các câu hỏi bên dưới
This is Nam. He is twenty-three years old and he is an engineer. There are five people in his family. His father, his mother, his two sister and him. His father is fifty and he engineer, too. His mother is forty -eight years old. She is a doctor. His sister are twelve and swventeen. They are student 
What is his name ?
How old is he ?
What does he do ? 
How many are there in his family ?
How old is his father ?  
Is his father an engineer ? 
How old is mother ? 
How old is sister ? 
What is his sister do ? 
Is his mother a nurse ?