坡长小于（）米时，必须设“二挡”，即平坡头自动复位阻车器和变坡点下常闭式罐挡。
A、35
B、40
C、70
D、20
参考答案：D
Guillain-Barre综合征的病理改变是（）
A.神经内膜血管周围炎症细胞浸润
B.血管周围炎症细胞主要为中性粒细胞
C.周围神经坏死
D.继发轴突变性
E.节段性脱髓鞘
用所给词的适当形式填空。
1.He often _______(do) his homework every day.
2.She___________(read)English now.
3.They are _______(go) to Hawaii for vacation.
4.Does your father________(speak)English?
5._________(send) me a postcard frrom Hong Kong,please
send) me a postcard frrom Hong Kong,please