Question 11. Doing regular exercise can help ______ your muscles.

     A. strongly                      B. strength                       C. strengthen     D. strong

Question 12. He was quite surprised ______ the final result.

     A. for                               B. at                                 C. of     D. from

Question 13. Simple actions like picking up litter on the street can ______ a difference to the environment.

     A. hold                            B. make                           C. keep     D. pay

Question 14. They will have dinner ______.

     A. when every guest was arriving                          B. since every guest arrived

     C. after every guest had arrived                             D. as soon as every guest arrives

Question 15. Those plastic bottles ______ instead of being thrown away.

     A. are reusing                  B. have reused                C. will reuse     D. can be reused

Question 16. When Clara lost her job last year, she plumbed the ______ of despair.

     A. weights                       B. lengths                        C. depths     D. widths