Choose the correct form of the verb: __ wear a helmet when riding a bike. A) can B) may C) must D) should Choose the correct form of the verb: It __ rain tomorrow, so bring an umbrella just in case. A) may B) must C) will D) can

The correct answers are:1. **C) must** "Must" expresses obligation or necessity. Wearing a helmet while riding a bike is a safety requirement.2. **A) may** "May" expresses possibility. It's possible it will rain, but not certain. "Will" implies a stronger prediction of certainty, while "must" implies necessity and "can" implies ability.