题目

For many years I worked in a downtown public service organization. Through my work I would encounter so many people 1 difficult times. Our doors were 2 to women and some families for any help we could 3 . We had a public 4 on our main floor with huge windows looking onto street. A number of times I saw a 5 passing by who looked 6 he was struggling in life and may 7 have been homeless. He would come into the cafeteria occasionally, 8 a coffee, then sit and sip it quietly in a corner. He often looked 9 at the home-style breakfasts being served. I was personally struggling with 10 as o函数．若在上存在,使得,则实数的取值范围是（    ）A．B．C．D．