11,Those students are interested...protecting the environment. ( by/ at/ in )

12,That beautiful toy is made from...paper. ( reduced/ reused/ recycled )

13, It is difficulf...people from littering. ( keep/ keeping/ to keep )

14, Doing exercises...can keep you fit. ( regular/ regulation/ regularly )

15, The girls are...from class A3. ( skip rope/ skipped rope/ skipping rope )

16, What...Mr Nam like? He's kind but strict. ( do/ does/ is/ can )

19, She...a lot since she became the president of the company. ( traved/ has traveled/ was traveled )

20, The Pikes...to visit Viet Nam yet. ( didn't come/ haven't come/ don't come )

GIÚP MÌNH GIẢI NHỮNG CÂU NÀY ĐC K Ạ