在2 L的密闭容器中,充入2 molN2和3 molH2,在一定条件下发生反应,3 s后测得N2为1.9 mol,则以H2的浓度变化表示的反应速率为 mol/(L·s)。
单词拼写。
1. He is not a good doctor because he is short of e_______ (经验).
2. Such b_______ (行为) is unacceptable in public.
3. She is studying American ________ (文学) at Georgetown University at present.
4. I think we all learned a ________ (宝贵的) lesson today.
5. Looking after a baby is as c_______ (具有挑战性的) as working on a new job.
6. In the final _______ (场景), Harry expressed his love to Julia.
7. — Are you close to your parents?
— Yes. I have a good r_______ (关系) with them.
8. His _______ (解释) are always difficult to believe.
9. The Internet is _______ at a very fast speed. (发展)
10. The students are working hard every day, in ______ (准备) for the big examination.
()是信息系统建设的参与者和最终使用者。
A.用户
B.系统分析人员
C.数据库管理人员
D.程序员