由-x2有意义，得-x2≥0，即x2≤0，
根据非负数的意义可知x2≥0，
所以，x=0．故选B．
It's said that __________ is going to give us a lecture.
A．an American famous young
B．a famous American young
C．a famous young American
D．a young famous American
快件登单要在生成总包后打印出封发清单。
