Hoàn thành các câu sau

is/am/are/aren't/isn't/am not 
13. I.........twelve years old(be)
14.Jim and Cathy.........at school (not be)
15. The elephants..........tired(be)
16.Mr,Cooper...........in the house (be)
17.The boys.............in the park (be)
18.The mouse...............in front of the hole(be)
19.Peter.............a clever boy (be)
20.I...........Sam(be)