A.which to use | B.how to use it |
C.what to use | D.where to use it |
A.happen | B.happened | C.to happen | D.happening |
A.working | B.work | C.to work | D.worked |
A.to repair | B.to be repaired | C.repaired | D.be repaired |
A.to open ; OK | B.to open ; Good idea |
C.opening ; Of course | D.opening ; Certainly not |
A.improve | B.improved | C.can improve | D.can be improved |
© 2017-2019 超级试练试题库,All Rights Reserved.