题目

第二节：完形填空（共20小题，每小题1.5分，满分30分）   阅读下面短文，从短文后所给各题的四个选项（A、B、C 和D ）中，选出可以填入空白处的最佳选项。 I put a package of small gold colored foil (金箔) angels in my purse after my illness. The package was ___36___ and the angels fell out into my purse.       On the way home, I was at the store __37____ for something and change was __38____. I dug in, got the change and gave it to the __39____. I didn’t realize there were also angels sticking (粘) to the ___40___! Well, she said,如图（a）所示，一个电阻值为R，匝数为n的圆形金属线圈与阻值为2R的电阻R1连接成闭合回路，线圈的半径为r1，在线圈中半径为r2的圆形区域内存在垂直于线圈平面向里的匀强磁场，磁感应强度B随时间t变化的关系图线如图（b）所示，图线与横、纵轴的截距分别为t0和B0导线的电阻不计，求0至t1时间内（1）通过电阻R1上的电流大小和方向；（2）通过电阻R1上的电量q及电阻R1上产生的热量．