下列物质中属于离子化合物的是
A.KCl
B.Ba(OH)2
C.H2O
D.NH4Cl
ABD
含有离子键的化合物是离子化合物,水中只有极性键,属于共价化合物。答案是ABD。
用括号中所给动词的适当形式填空
1. Don't spend too much time __________(chat) on the Internet.
2. We always have a great time __________(study) English.
3. Our teacher asked us __________(open) the windows.
4. What games __________ they __________(play)? Let's go and have a look.
5. Simon __________(go) to the club last night.
老年人消化系统的主要变化包括
A.胃肠蠕动减慢,胃排空延慢B.膀胱容量减少C.儿茶酚胺含量减少D.胸式呼吸减弱,腹式呼吸相对增强E.甲状腺功能降低