⑴根据电流所产生的效应认识电流
⑵研究电流时把它比作水流
⑶利用磁铁产生的作用来感知磁场
⑷利用磁感线来描述磁场
将左边和右边的句子连成对话。
①Is this your bed? ____ a. Hi, Joe.
②Are these your pens? ____ b. No, it isn't.
③Your book is nice. ____ c. Thank you.
④Hi, Peter. ____ d. Six yuan, please.
⑤How much are they? ____ e. Yes, they are.
