A:NaOH
B:Na2CO3•10H2O
C:Na2CO3
D:NaHCO3
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.
如图所示,表示物体做匀速直线运动的是( )