易燃、易爆管道防止产生静电火花的措施就是安装可靠的接地线路，接地总电阻不得超过（）Ω。
A.10
B.9
C.8
D.7
参考答案：A
Yesterday she went to school _____. [ ]
A. as usually
B. as usual
C. usually
D. like usual
设有定义：int n=0,*p=&n，**q=&p;,则以下选项中，正确的赋值语句是 ______。
A) p=1; B) *q=2 C) q=p D) *p=5
