问题
多选题
下列关于磁性材料及其应用的说法正确的是[ ]
A．高温下，磁性材料会产生退磁现象
B．磁卡背面的黑条是用做磁记录的磁条
C．电磁铁是用硬磁性材料制成的
D．缝衣针、螺丝刀等钢铁物质与磁铁接触后不会被磁化
答案
AB
搜题请搜索小程序“爱下问搜题”
下列关于磁性材料及其应用的说法正确的是[ ]
A．高温下，磁性材料会产生退磁现象
B．磁卡背面的黑条是用做磁记录的磁条
C．电磁铁是用硬磁性材料制成的
D．缝衣针、螺丝刀等钢铁物质与磁铁接触后不会被磁化
AB
阅读短文，然后完成短文后的表格，每空一词。 From 8：30 pm to 9:30pm on Saturday, March 23rd, 2013, a great number of people around the world turned off the lights for Earth Hour. It is a bit like an environmental New Year, providing a chance to help care for our earth and make people around the world learn how important it is to do that. What did you do for Earth Hour this year? Let’s share the Earth Hour stories. Emma was on one of the mountains near the city and took photos of my city. It was great to watch the stars and the moon after a busy day that she could enjoy this relaxing moment. Albert works as a waiter in a restaurant. Their restaurant was still open even for Earth Hour as they got lots of reservations(预定) that night. So they spent the hour working by candlelight. And guess what? Their customers loved that and promised to come for next Earth Hour. Brandon turned off the main power to his house and went for a walk for Earth Hour. It was a little strange to walk in the dark, but it was only for one hour. Just think of what it must have been like before the invention of light bulb! Mary invited her friends who know and support Earth Hour activities. They actually had a candlelight and they talked about the old happy days that they spent together in college. Information Card
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