To vs For practice

I need my computer ________ send an important mail.

Call your doctor ______ an appointment.

I'm on a diet _____ lose some weight.

I'm going to call the restaurant ______ book a table.

A thermometer is a tool _____ measuring the temperature.

Do you have time ________ a cup of tea?

I need some money ____a taxi:

I need some money ______ take a taxi.

This knife is used ______ cutting plastic.

Where can I go ______ buy the ingredients?