Mary ate a banana a few minutes ago

11. Mary ate a banana a few minutes ago. 
They have just 
12. He left his house a few minutes ago.
 He has just
13. My parents send me some money every month.
 I 
14. The gardener waters the plants every day. 
The plants 
15. Peter wrote a novel. 
The novel
16. Jane did a lot of homework .
 A lot of 
17. People built the bridge last year.
 The bridge
18. You must do this test carefully. 
This test
19. They grow rubber trees in tropical countries. 
Rubber trees
20. Children should drink milk every day. 
Milk