Tran Huu Giang | English 10 | E-learning Course

We can use gerunds and infinitives to describe the purpose of something
* Infinitive: use sth. / sth. is used + to-infinitive
* Gerund: for + V-ing

Examples:
A ruler is used to draw straight lines.
A ruler is used for drawing straight lines.
We can use a ruler to draw straight lines.