1.Traffic problem in the city will remain just the same _____people observe traffic regulations more carefully.
A.when B.unless C.if D.because
KEY:C

2.Could it be in the restaurant in _____you had dinner with me yesterday_____you left dehind your keys and wallet?
A.what;when B.where;that C.that;where D.which;that
KEY:B

3.The generation gap seems to be wider and wider with the rapid changes in technology,education,transportation and communication that_____all over the globe.
A.are taking place B.took place
C.have taken place D.will take place
KEY:A

第一题应该是B。
第二题应该是D。
强调句与定语从句结合
Could it be in the restaurant （①in _____you had dinner with me yesterday）_____you left dehind your keys and wallet?
A.what;when B.where;that C.that;where D.which;that
①为定语从句，修饰restaurant。
剩余部分为强调句（It could be ...that）强调in the restaurant。
第三题选A。现在进行表示现阶段正在发生的事。全球科技、教育等的变化是一直在持续的。所以用现在进行时。