根据二次根式有意义，分式有意义得：x≥0且x-1≠0，
解得：x≥0且x≠1．
故答案为：x≥0且x≠1．
颅骨牵引的重量一般为第1、2颈椎用4kg，其余椎体的牵引重量为（）。
A.每下1个椎体
B.每下2个椎体
C.增加1kg
D.增加2kg
E.增加3kg
Which statement pertaining to log keeping is TRUE?（）
A.Entries relating to pre-voyage，pre-departure and daily tests are required
B.Both A and C
C.All distress，urgent and safety communications must be logged
D.Routine daily MF-HF and INMARSAT-C transmissions do not have to be logged
