下列哪一种工具不适合用于清除较轻的腐蚀产物（）？
A.砂纸
B.纱布
C.砂轮
D.打磨垫
参考答案：C
Tommy had had a three-mile drive north _____ he could turn and head back south.
A．while
B．as
C．before
D．after
肺癌的分布情况，左肺多于右肺，下叶多于上叶。()
