Gerunds & Infinitives - Choose the right one!

I used the knife _____ (opening / to open) the letter.

It´s no good _____ (to cry / crying) every time you have a problem to face.

_____ (To buy / Buying) a new computer, you need to think carefully what you want.

There´s just no point _____ (to argue / arguing) with them.

It´s essential ____ (to think / thinking) before you answer.

Does _____ (to think / thinking) about food make you hungry?

I certainly don´t mind _____ (to wait / waiting) for you.

They managed to resolve the problem without ____ (to lose / losing) face.

In my family, I´m usually the first person _____ (to wake / waking) up.

Can you manage _____ (seeing / to see) what´s happening?