二叉树由三个基本单元组成,即左子树,右子树和 【4】 。
参考答案:根节点
解析: 二叉树由根节点、左子树和右子树组成。
在室温时,下列各组中的物质分别与过量NaOH溶液反应,能生成5种盐的是[ ]
A.A12O3、SO2、CO2、SO3
B.C12、A12O3、N2O5、SO3
C.CO2、C12、CaO、SO3
D.SiO2、N2O5、CO、C12
请用所给动词的适当形式填空。
1. She ____________ (like) her brother very much.
2. I ____________ (not go) to school by bike every day.
3. We usually ____________ (get) up early in the morning.
4. Lucy ____________ (not sing) very well.
5. ____________ (be) Mary ____________ (have) an English class now?
6. My mum ____________ (do) housework at home. She ____________ (not have) a job.
7. Miss Lee usually ____________ (help) me with my lessons.
8. He ____________ (do) homework and ____________ (watch) TV in the evening.
9. I like ____________ (read) books and ____________ (dance) after school.
10. Lily is ____________ (play) the piano now.