갈다 in English:

Sharpen your pencil.

I want a knife to sharpen my pencil with.

What objects can be sharpened when they become blunt? Pencils can be sharpened when they become blunt.

Ted knew that the only way to sharpen his computer skills was to go to evening classes.

the marketization of everything sharpens the sting of inequality

Make sure you sharpen your pencils before the test begins.

to make a feeling stronger and more urgent: A series of attacks have sharpened fears of more violence.

I have to sharpen this knife. It's too dull.

You have to sharpen a blunt pencil.

My admiration for the professionals has sharpened considerably.

May I sharpen my pencil?

You need to change your behaviour.

The tenants want to change the terms of the agreement

I need to change my plans. / You need to change your behaviour. / The internet is really changing the way we do business too.