输注血小板时输注速度应缓慢，以免发生输血反应。
参考答案：错
—Hello, this is Lily speaking.Could I speak to Mr. Black?
—…Sorry. He ______ the Xuanwu Lake Park. [ ]
A. has been to
B. went to
C. has gone to
D. will go to
若关于x的一元二次方程x2+（2k+1）x-2+k2=0有实数根，则k的取值范围是______．
