II Choose a good topic sentence to begin each of the following paragraphs.
1.
A. It is a great idea for middle school students to take a part-time job.
B. Middle school students should study hard and take a part-time job in their free time.
They can learn many things that are not usually taught in a classroom. For example, they can learn how to communicate with different people. Having a part-time job also gives students a sense of independence. They can earn money on their own instead of asking their parents for it. Moreover, having a part-time job can help students learn what the real world is about.
2.
A. Smart phones are popular and a study shows eight out of ten teenagers have smart phones.
B. Smart phones are playing an important role in our daily life.
They can make our life interesting. We can use them to take photos, listen to music and make videos. Besides that, our life becomes more convenient with the help of a smart phone. If we have the Internet, we can check emails, search for information and images for our school projects and even shop online.

1.A 2.B

1. 段落主要阐述中学生做兼职的好处，如学习课堂外知识、获得独立感、了解真实世界等。A选项“中学生做兼职是个好主意”能概括这些好处，引出下文；B选项“应该努力学习并在空闲时间做兼职”重点包含了学习和兼职两方面，而段落未提及学习，A更合适。
2. 段落讲述智能手机让生活有趣（拍照、听音乐等）和方便（查邮件、搜信息、网购等），B选项“智能手机在日常生活中扮演重要角色”能总领这些内容；A选项“智能手机流行及青少年拥有率”只是现象陈述，未体现其作用，B更恰当。