ing vs to infinitive special cases

He tried ____ the equation, but it was too difficult.

• solving

• to solve

They tried ___ math to kids with computers and were surprised by the good results.

• to teach

• teaching

You forgot ____ your computer, so your overly attached girlfriend read all your emails.

• to lock

• locking

I'll never forget ____ that summer in Pontevedra with my friends.

• to spend

• spending

I remember ___ to school in a horse buggy driven by my dad.

• going

• to go

Remember ___ the lights when you leave.

• turning off

• to turn off

Last year I stopped ___ new year, and then I went on working. Such is the life of a programmer.

• celebrating

• to celebrate

I stopped ___ carbs two months ago and now I feel much better.

• to eat

• eating