Your Modal Verb Quick Guide

Use these rules to sound natural every time:

• Can for ability and informal requests: "Can you pass the salt?"
• Could for polite requests: "Could you send that by Friday?"
• Should for advice and mild obligation: "You should check the reviews first"

Modals are the volume knob of English. Turn them up for formality, turn them down for casual talk. Practice switching between "can" and "could" in the same conversation and watch how people respond differently.