Em hãy điền động từ “to be” thích hợp để hoàn thành những câu sau

1. We are school children. We ----- thirteen years old.

2. – “How__________ you, John?” – “I ______________ fine, thanks.”

3. Those new desks___________ in their classroom.

4. My mother___________ cooking the meal in the kitchen now. 

5. The students__________ camping yesterday so today they_________tired.