手工气体保护焊设备主要由（）等部分组成。
A.焊接电源
B.控制系统
C.供气系统
D.焊枪
E.点火器
参考答案：A, B, C, D
— You've forgotten _______ the milk again, Mike.
— I'm 'afraid so. But I don't remember you ________ me to buy it. [ ]
A. to buy; to tell
B. to have bought; to have told
C. having bought; were telling
D. to buy; telling
设a = 8，则表达式 a > > > 2的值是【 】。
