∵原方程有增根，
∴最简公分母x-4=0，
解得x=4．即增根为x=4．
驱动机与泵连接时，应以泵的（）为基准找正。
A、外边界
B、中心线
C、底边
D、轴线
________ they decide which college to go to, students should research the admission procedures.[ ]
A. As
B. While
C. Until
D. Once
