磁流体推进船的动力来源于电流与磁场间的相互作用.如图16-31所示是在平静海面上某实验船的示意图，磁流体推进器由磁体、电极和矩形通道(简称通道)
Saying that is just like ______ fuel ______ the fire. A. to add, to B. being added, to C. to be added, to D. adding, to
完形填空。Hello, boys and girls! I __1__ Frank Smith. Frank is my __2__ name. Smith is my__3__ name. This is __4__ backpack. It is black. Oh, that is __5__ eraser. It’s __6__. But （但是
氢氧化铝可作为治疗胃酸过多的内服药，这是利用了氢氧化铝的A. 酸性 B. 碱性 C. 两性 D. 氧化性
有甲、乙两运动员做接棒练习，甲在接力区前s0＝18m处作了标记，并以v1＝8.5m/s的恒定速度跑到此标记时向乙发出起跑口令，乙在接力区的前端听到口令
在图5所示的电路中，电源电压不变，当电键S由闭合到断开时，电压表V1的示数将__________，电流表A的示数将__________。S断开后，将滑片向右移动，则电流
.My sister still wants to go to school ____she is ill.A．although B．forC．butD．and
