选用于最后孤立，并向近中舌向倾斜的下颌磨牙的卡环是
A．回力卡环B．圈形卡环C．长臂卡环D．对半卡环E．BPI卡环
参考答案：B
It's true that the old road is less direct and a bit longer. We won't take the new one, ______, because
we don't feel as safe on it. [ ]
A. though
B. therefore
C. too
D. while
对脑震荡的诊断，主要依据是（）
A.头皮擦伤
B.颅骨骨折
C.生命体征的变化
D.头痛、呕吐
E.短暂昏迷和逆行性健忘
