Sally is a good girl. She never ____  up late. Her mother wakes her up（唤醒）at 6:00 a.m. From a quarter ____  six, she begins to do sports. The she comes back and has ____  at six forty. After that, she goes to school. Sometimes she ____ her bike.
At school, Sally has seven classes on ____ . Sally is good at（擅长）English. She san speak English very well. After school she often plays ____  games with her ____ . Then she goes home by bus. She gets home before 6:00 p.m.. After
____  she begins to do her ____ . Then she ____  TV for a while, she always goes to bed before half past ten.

如图，已知二次函数 的图象经过A（2，0）、B（0，－6）两点.

请将血液成分与其对应功能用直线连接起来．

血浆____                 ①运输氧气

红细胞____              ②运输养料和废物

白细胞____              ③促进止血并加速凝血

血小板____              ④防御疾病

对于x∈R，式子$\frac{1}{\sqrt{k{x}^2+kx+1}}$恒有意义，则常数k的取值范围是（　　）