当机动车白天驶入黑暗隧道时，提前降低车速，使驾驶人适要光线变化。
参考答案：对
The following structures pass through the infrapiriform foramen, EXCEPT （）.
A．superior gluteal artery.
B．sciatic nerve.
C．posterior femoral cutaneous nerve.
D．pudendal nerve.
E．internal pudendal vein and artery.
治理黄河的根本措施是[ ]
A、梯级开发
B、修筑长堤
C、疏通河道
D、水土保持
