Chọn đáp án đúng: One way of preventing further flooding would be to _______ the river bed

16/ One way of preventing further flooding would be to _______ the river bed.
        A. deep                       B. deepen                   C. deeper                    D. depth
17/ It is important to educate children before they become sexually _______.
        A. act                         B. active                     C. action                     D. actor
19/ Now you know all the facts, you can make an informed _______.
        A. choice                    B. choose                    C. chooser                  D. choosing
20/ The company's new model will be going into _______ early next year.
        A. produce                  B. producer                 C. products                 D. production
21/ You _______ change trains at Peterborough if you're going to Newcastle.
        A. could                     B. should                    C. did                         D. would
22/ You _______ have a piece of cake after you've eaten your vegetables!
        A. can                        B. could                      C. shall                       D. might
23/ If you show the receipt, there _______ to be any difficulty getting your money back.
        A. shouldn’t                B. couldn’t                  C. didn’t                     D. oughtn't
24/ They knew there _______ be trouble unless the report was finished by the next day.
        A. ought to                 B. should                    C. would                     D. must
29/ There are, _______ you don't mind me saying so, one or two problems with this plan.
        A. if                           B. provided                 C. in case                    D. as long as