阅读下面短文，用括号内所给动词的适当形式填空（必要加助动词或情态动词） The largest problem among teenagers is that they are too stressed. Mary, a 26-year-old girl, 1.(worry) about her exams very often. Although she 2. (study) English for three years, and is good at it, she is still afraid of English exams. Last night, after 3. (come) back home, she 4. (begin) to get ready for her English exam. While she 5. (read) English books, her mother said to her, “Come on, dear! It’s time 6.( .have) supper!” But Mary 7.( not listen) to her mother. She went on reading. Her mother went on, “Mary, I believe you. You can pass your exam tomorrow.” But Mary still went on studying. At 11:30 the light in her room 8. ( be )still on. Her mother said to her, “I think teenagers 9.( go) to bed earlier before exams than usual.” Mary agreed, but she 10. (not fall)asleep. She was too nervous. Maybe it is time to solve the teenagers’ problems.