题型:名词解释 John is very________. If he promises to do something he'll do it. [ ]A. independent B. confidentC. reliable D. flexible 查看答案
题型:名词解释 磁悬浮列车在平直的路面上匀速行驶时,列车水平方向上所受合力______(选填“向前”、“向后”或“等于零”),此时列车相对于路旁的树木是______(选填“运动”或“静止”)的. 查看答案