50.A.don’t B.do C.did D.didn’t
49.A.touch B.feel C.catch D.hold
48.A.order B.suggestion C.rule D.requirement
47.A.others B.another C.else D.also
45.A.cold B.warm C.wash D.bath
44.A.may B.can C.must D.will
43.A.light B.power C.plug D.electricity
42.A.push B.drag C.pull D.draw
41.A.at B.of C.for D.on
40.A.reasons B.causes C.difficulties D.problems