搜题请搜索小程序“爱下问搜题”
问题 单项选择题

汞接触者尿汞升高的意义是

A．急性汞中毒诊断指标

B．慢性汞中毒诊断指标

C．汞吸收障碍

D．汞吸收指标

E．尿汞排泄障碍

答案

参考答案：D

解析：尿汞升高，通常无明显中毒症状，可作为汞作业工人的汞吸收指标。

填空题

根据括号内所给单词的适当形式填空。

1. He _______ (hang) with his friends last night so he get up late this morning.

2. There are many _______ (visit) in Huang Shan every year.

3. Who _______ (teach) you English last term?

4. We are having a _______ (meet) the day after tomorrow.

5. Mei Lanfang _______ (become) a Beijing Opera actor when he was ten.

6. Everyone should _______ (sleep) for more than eight hours to be healthy.

7. We went _______ (camp) on our last school trip.

8. What did you _______ (buy) for Li Fang as a present?

9. It looks _______ (like) her mother very much.

10. He _______ (real) likes to watch TV shows.
查看答案
单项选择题

下列关于数据库系统的叙述中，正确的是______。

A．数据库系统只是比文件系统管理的数据更多

B．数据库系统中数据的一致性是指数据类型一致

C．数据库系统避免了数据冗余

D．数据库系统减少了数据冗余
查看答案