A. What, tallest
B. Who, tallest
C. What, the tallest
D. Who, the tallest

1. It took us 2 hours to finish the work. (改為同義句)
    We ______ 2 hours ______ the work.
2. Tom is taller than any other boy in his class. (改為同義句)
    Tom is ______ ______ boy in his class.
3. They had lunch at school yesterday. (改為否定句)
    They ______ ______ lunch at school yesterday.
4. The Olympic Games are held every four years. (對畫線部分提問) 
    ______ ______ are the Olympic Games held?
5. The government didn't want foreign engineers because they wanted a
     Chinese engineer for a Chinese railroad. (對畫線部分提問) 
    ______ didn't the government ______ foreign engineers?