平行四边形的周长为240,两邻边为x、y,则它们的关系是( ).
A:y=120-x(0<x<120)
B:y =120-x(0≤x≤120)
C:y =240-x(0<x<240)
D:y =240-x(0≤x≤240)
- I don't know Kate's address. Do you know _______?
- Sorry, I don't know, either.
Food is very important to our health. Everyone needs to eat well if he or she wants to have a strong body.Our minds, like our bodies, always need the best food. This kind of food is knowledge. We start getting knowledge when we are very young.
如图为某生物体细胞中基因位于染色体上的示意图,有关该图解的叙述正确的是( )