Acid rain destroys forests and has a serious impact on ecosystems.

That building is very old.

This metal is undergoing corrosion.

Acid rain corrodes the surface of buildings.

The acidity of this lemon is very strong.

The surface of the table is smooth.

When I looked out the window, it was raining.

I like to read books at home on rainy days.

Rainy days make me feel down.

The reason why water droplets become round is due to surface tension.