Yao Ming wants to set up a Hope Project School, ________poor children in remote areas to receive education.
A:aims at helping
B:aiming at helping
C:aims to helping
D:aimed to help
关于x的方程 =a−1无解,则a的值是____。
在“测定小灯泡额定功率”的实验中(小灯泡标有“3.8V“字样,灯泡的电阻约为12Ω):