Fordetectingquicksandtheauthorrecommends______.
A.goodeyesight
B.fastthinking
C.theuseofalongpole
D.testingthesurfacewithyourshoe
正确答案:C[解析]见第三段,探索杆或长棍可以用来测试流沙。

Fordetectingquicksandtheauthorrecommends______.
A.goodeyesight
B.fastthinking
C.theuseofalongpole
D.testingthesurfacewithyourshoe
正确答案:C