A:Must
B:May
C:Need
D:Will
选用方框内适当的句子完成对话,只填序号。
A、Thank you.
B、I'd like some soup, please.
C、Anything else?
D、Would you like some juice?
E、Would you like a knife?
不改变分式的值,把下列各式的分子、分母中的各项系数都化为整数,且使分子和分母不含公因式.
(1)12a+13b23a-14b;(2)45x+0.25y12x-0.6y.
下列有关人类反射知识的描述错误的是( )