1. The circuit of the city walls is three miles. 环绕本市城墙的周长是三英里.
2. A short circuit will blow the fuse. 发生短路时, 保险丝就会被烧断。
3. A magnet has two poles. 一块磁铁有两极。
4. Last fall, the Hyde Foundation opened a magnet program within a public high school in the suburbs of New Haven, Connecticut, over parents' protests. 去年秋天,在家长的一片抗议声中,海德基金会在康涅狄格州纽黑文市郊区的一所中学内启动了一个引人注目的教学计划。