关于曲线运动的速度，下列说法正确的是（ ）
A：速度的大小与方向可能都在时刻变化
B：速度的大小不断变化，速度的方向不一定发生变化
C：速度的方向不断发生变化，速度的大小也一定发生变化
D：质点在某一点的速度方向是在曲线上这一点的切线方向上
Li-Al/FeS电池是一种正在开发的车载电池，该电池中正极的电极反应式为：2Li+ + FeS + 2e- = Li2S + Fe ，有关该电池的下列叙述中正确的是（ ）
A
Linda，14
My mother does most of the housework like cooking and folding the clothes.My father can only do the washing，sweep the floor and take out the rubbish.He really needs to learn how to do the housework.
Celina，13
My mother and my father do 50% of the housework each.My mother does the washing and cleans the living room.My father makes the bed and drives me to school.
Paul，16
My father doesn't do a lot but he tries to help.He hangs__up the clothes after my mother washes them and my mother is happy that he always gives her a hand.
Bill，15
My mother is a doctor.She is busy with her work every day，so she has little time to do the housework.In fact，she isn't good at doing it.So my father has to do most of it.Sometimes my grandmother comes to help.
