21.We'd better hurry ______ it is getting dark.
A.and B.but C.as D.unless
22.I didn' t manage todo it _____ you had explained how.
A.until B.unless C.when D.before
23._____he comes,we won't be able to go.
A.Without B.Unless C.Except D.Even
24.I hurried _____ Iwouldn't be late for class.
A.since B.so that C.as if D.unless
25._____ I catch a cold,I have pain in my back.
A.Every time B.Though C.Even D.Where
26.What's the matter _____ they still haven't answered the telegram?
A.when B.that C.though D.however
27.Bring it nearer _____ I may see it better.
A.although B.even though C.so that D.since
28.You may arrive in Beijing early _____ youmind taking the night train.
A.that B.though C.unless D.if
29.Helen listenedcarefully _____ she might discover exactly what she needed.
A.in that B.in order that C.in case D.even though
30.More people will eat out in restaurants _____ they do today.
A.than B.when C.while D.as