属神经毒类的毒蛇是
A．蝰蛇
B．竹叶青蛇
C．尖吻蝮蛇
D．海蛇
E．眼镜蛇
参考答案：D
. Some animals are in danger, and the scientists are doing ___ they can ___ them.
A．that; to save
B．whatever; to save
C．what; save
D．the thing; save
检查砂浆饱满度用（）。
A、托线板
B、温度计
C、漏斗
D、百格网
