Common Modal Verb Errors They should to check the weather before they leave. ✖ She can play the guitar after dinner. ✔ She can swim very fast in the pool. ✔ He can speaking three languages fluently. ✖ Common errors when using English modal verb structures The modal auxiliary verbs below use the structure "modal verb + infinitive" (without 'to') can, could, may, might, must, shall, should, will, would Examples: When traveling, we should respect the customs of the countries we visit. (NOT should to respect; should respecting) You must wear a helmet when cycling to protect your head in case of an accident. (NOT must to wear; must wearing) Can you help me with this project? I believe your expertise would greatly benefit our team. (NOT can to help; can helping) In emergency situations, you might need to act quickly to ensure everyone's safety. (NOT might to need; might needing) Modal verb questions and negatives do not use t