Showing purpose

        (Followed by infinitive)
        She is saving money to buy a new car.
        The company will reduce prices in order to increase sales next year.
        Cyclists must wear a helmet not to get hurt in case of accident.

        (Followed by a sentence usually including a modal verb)
        The library will be open until 12 p.m. so that  the students can prepare for their exams.
        Her parents sent her to a British school so that she could learn English at an early age.