There are sixty minutes in ______ hour. [ ]
A. a
B. an
C. the
答案：B
— What has fur?
— __________.[ ]
A. An elephant
B. A tiger
C. Fish
焊接接头质量可通过（）等方式进行。
A.外观检验
B.焊缝内部检验
C.机械性能检验
D.密封性检验
