下列离子反应方程式正确的是( )A.铜和硫酸锌溶液：Cu+Zn2+====Cu2++ZnB.澄清的石灰水中加入少量NaHCO3溶液：Ca2++2OH-+2==== CaCO3↓+2H2O+C.少量的盐酸逐滴滴
肾上腺素可用于支气管哮喘过敏性反应，其结构简式如下。下列关于肾上腺素的叙述正确的是 （ ） A．该物质
It was such a long way that they didn't the hotel until it became dark. A. reach B. arrive C. get
在DNA分子的一条单链中相邻的碱基A与T的连接是通过( ) A.肽键 B. —磷酸—脱氧核糖—磷酸— C.氢键 D. —脱氧核糖—磷酸—脱氧核糖—
下图是兔和狼的牙齿分化示意图，据图回答：（1） 是兔的牙齿， 是狼的牙齿。（2）标出图中数码所示的名称：① ②
Remembering names is an important social skill. Here are some ways to master it. Recite and repeat in conversation. When you hear a person's name, repeat it. Immediately say it to yourself several t
已知|2x＋1|＋(y－2)2＝0，求(xy)2 011的值．
)=
,则∠A= .