下列哪些是腕管综合征的前置因素（）
A.腕横韧带瘢痕
B.桡骨下端骨折
C.蚓状肌肌腹过高
D.屈指肌腱肌腹过高
E.腕管内脂肪瘤
参考答案：A, B, E
Today, we'll discuss a number of cases ____ parents have much difficulty in communicating
with their children.[ ]
A. which
B. that
C. where
D. why
在元素周期表中最容易找到半导体材料的合理位置是[ ]
A．金属元素和非金属元素交界处
B．过渡元素区
C．周期表右上角
D．周期表左下角
