81.Yocan go out yoPromise to be back before 10 o’clock.

A.now that

B.so long as

C.so that

D.as far as

82.Dr.Bethune began to work he arrived at the front.

A.the moment

B.by the time

C.before

D.at the moment

83.We had to be patient because it some time we got the full result.

A.have been;since

B.had been;until

C.was;after

D.would be;before

84.l won’t give yoany help yotell me the truth.It’s none of my business.

A.unless

B.since

C.if

D.even if

85.The roof fell he had time to dash into the room to save his baby.

A.before

B.as

C.after

D.until

86.-Let Jack take the place.He’s older and should be more experienced.

-I don’t think so.A man doesn’t necessarily grow wiser he grows older.

A.because

B.that

C.than

D.as

87.younderstand this rule,yowill have no further difficulty.

A.While

B.Once

C.Though

D.Unless

88.I’ll give him your message he comes back from lunch.

A.until

B.as soon as

C.while