问题
选择题
He be a history teacher.[ ]
A. used to
B. be used to
C. use to be
D. be use to
答案
答案：A
搜题请搜索小程序“爱下问搜题”
He be a history teacher.[ ]
A. used to
B. be used to
C. use to be
D. be use to
答案：A
在(0，+∞)上恰有一实根，求其中常数k的取值范围．