In this task, you need to write a topic word from the given fact. The topic word must have at least one word overlap with the given fact. The topic word often involves adding a new word from a related concept. In your topic word, use at least one word from the given fact. Topic words with two or more words work best.

[Q]: Fact: when a metal rusts , that metal becomes orange on the surface.
[A]: metal iron.


[Q]: Fact: Hydrogen bonds cause water to expand when it freezes.
[A]: freezes.


[Q]: Fact: a freezer is used for cooling things.
[A]:
cooling food helps it last longer.