13. We worked all day and picked up over four tonnes of trashes.

                 A                   B                                       C             D

14. I play basketball with my classmates yesterday. We had so much fun.

          A                       B                                                     C          D

15. People should to call the police if there’s a stranger around their houses.

                     A         B                              C                                   D

16. Volunteers can help take care for and play with the homeless animals.

             A                 B                    C                                    D