靠板体两端安装挡板，其作用是保证靠板平行移动。
参考答案：对
"To help out" means "to volunteer" or to give help where it ? [ ]
A. need
B. to need
C. is needed
反乌头的药物是（）
A.甘遂
B.瓜蒌
C.苦参
D.赤芍
E.海藻
