题干

定义域为R的函数fx满足fx+2=2fx,当x[0,2)时,fx=x2-x,x[0,1),-
1
2
x-
3
2
,x[1,2),
则当x[-4,-2)时,函数fx
t
2
4
-t+
1
2
恒成立,则实数t的取值范围为(   )

A:2t3

B:1t3

C:1t4

D:2t4

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答案(点此获取答案解析)

B

同类题1

阅读下面短文, 从短文后各题所给的四个选项(A、B、C、D)中, 选出可以填入空白处的最佳选项。

    Chelsea's father had always been concerned about him from the very beginning. When Chelsea was in senior school and got eight A's and two B's, his father asked about the B's. Later, as he grew up and1 the wonderful girl he was in love with, his father warned that she might be 2 from what he thought. No matter what Chelsea did, it was3 enough to satisfy his father.

    Chelsea's father was 4 when Chelsea decided to take a job in another town. He tried to5Chelsea's plan, so he explained the6 of being close to the family and the dangers and the difficulties of living in a completely new place. 7,Chelsea shouted,“Dad,I'm moving to get away from you! I love you,but I can't 8the way you tear down everything I do.”

    He kept up his spirits for his father's counterattack (反击), but 9 the first time in his life he saw his dad's mask of confidence 10 .With tears in his eyes, his dad said 11,“All I ever wanted was to make you better and help you reach your goals and 12 failure. It's what I do. It's 13 my business is so successful. Do you want me to pay no attention to my 14, just stand by and not say anything or be a cheerleader?”

     “Dad,our 15 hasn't been good, because you care only about your own advice,” Chelsea 16. “You're my dad Sometimes I need praise more than a push. 17 trying to make me better just makes me feel worse. It's not 18 that you just love me and push me forward. I also need you to 19 me.” Sometimes we just need others' 20 more than advice.