额定触发角稳态运行一般为15°，保持在±（）°。
A.1
B.2.5
C.5
D.10
参考答案：B
You _____ the exam but you failed this time. [ ]
A. are supposed to pass
B. supposed to pass
C. are supposed passing
设有定义int k=1,m=2；float f=7；,则以下选项中错误的表达式是【 】。
A．k=k＞=k
B．k++
C．k%int(f)
D．k＞=f＞m
