题目

读一读，选择合适的答语。⑴Can I play with your rabbits? A. Of course, you can.⑵Where is Fido now?B. No, it isn't.⑶Is the dog climbing? C. Yes, they are.⑷Are they reading book in the classroom?D. He is reading books.⑸What is Mike doing? E. It is in the park. 答案：【1】A【2】E【3】B【4】C【5】D1．如图所示，磁场方向垂直纸面向里，磁感应强度大小为B．半径为r的圆环垂直于磁场，把圆环的一半置于匀强磁场中，则穿过圆环的磁通量为（　　）A．2πBrB．πBrC．$\frac{1}{2}$πBr2D．πBr2