《2025年快乐过暑假江苏凤凰科学技术出版社八年级提优版》

4. 某同学用甲、乙两种具有恒温功能的热水壶同时加热相同质量的水,甲壶比乙壶加热速度快,当水加热到70℃后,开始维持恒温。在一段时间内,水温y(℃)与加热时间x(s)之间近似满足一次函数关系,根据记录的数据,画函数图像如图：
(1)加热前水温是____10____℃；
(2)求乙壶中水温y关于加热时间x的函数表达式；$y=\frac{3}{8}x+10$
(3)当甲壶中水温刚达到70℃时,求乙壶中的水温。$55^{\circ}C$

答案：
(1)10
(2)$y=\frac{3}{8}x+10$
(3)$55^{\circ}C$

(C)1. —______ good time it is ______ around the countryside in autumn!
—Yes, I agree.
A.What a; driving
B.How; driving
C.What a; to drive
D.How; to drive

答案： C

2. —Is your hometown B?
—Yes. It's about 350 kilometres B Nanjing.
A.far away; far from
B.far away; away from
C.away; away from
D.away; far away from

答案： B

3. —Look at the bees flying C flowers.
—Yes, they are busy making honey.
A.around
B.across
C.among
D.between

答案： C

4. Lucy was as A as Lily because they got good grades in the exam.
A.happy
B.happier
C.happiest
D.the happiest

答案： A

5. —D is the best time to visit the city of Tianjin?
—Any time you like!
A.Why
B.How
C.Where
D.When

答案： D