Complete the task. Mike is an eco-helper. He is giving some recommendations for the people who care about nature. Choose the correct modal verbs to complete his statements.

Choose the correct option.

You [must|mustn't] pick up flowers here. It's a forbidden.

You [should|shouldn't] reuse or recycle some materials. It will help the ecology of your area.

You [can't|can] walk instead of using public transport if you live near your school.

You [can|can't] donate money to the ecological organisations if you have an opportunity.