电器设备保护接地后，其接地电阻越小，流过人体电流（）。
A.越大
B.越小
C.不变
参考答案：B
Tom _____ his father and his father _____ young.[ ]
A. looks like; looks like
B. looks like; looks
C. looks ; looks like
D. looks; looks
硬膜上穿刺孔的愈合时间为（）
A.24小时
B.48小时
C.72小时
D.1～2周
E.3周以上
