阅读短文,回答问题。
Seeing the Doctor
Mum: What is the matter, my son?
Son: My head is hurting. I can't go to school.
Mum: Come with me to the doctor.
Son: The doctor! Oh, no! My head is not hurting. I can go to the school.
减少二氧化碳的排放量要从我做起,下面你个人能做到的是( )
探究酒精对水蚤心率的影响实验的目的是( )
沿固定斜面下滑的物体受到与斜面平行向上的拉力F的作用,其下滑的速度﹣时间图线如图所示.已知物体与斜面之间的动摩擦因数为常数,在0~5s,5~10s,10~15s内F的大小分别为F1、F2和F3,则( )