Q）
A few pieces of iron(铁tiě) nails(钉dīng) were put into a beaker of water next to an open window. After a fes days, the water turns brownish.
What is the conclusion? C
A) The water reacted with sunlight.
B) The water mixed dust and dirt.
C) The water and air reacted with the nails.
D) The water heated by the sunlight reacted with the nails.
