下表是近代中国工业发展初期(1872-1911年)设立的厂矿数目统计表。结合近代经济

根据括号中所给的汉语写出单词，使句子意思完整正确。

1. The students all stood up when the teacher _______ (进入)the classroom.

2. Mr Green put a lot of ______ (努力)into arranging the concert.

3. The world ______ (哀悼)the loss of a great humanitarian.

4. China is trying her best to develop its agriculture and _______ (工业).

5. He worked very hard, and _______ (赚到) a lot of money.

6. Gong Li is a famous Chinese _______ (演员).

7. The old man died of ________ (癌症).

8. Girls mostly like ________ (浪漫的) films.

关系中的“主码”不允许取空值是指哪种约束规则

A．实体完整性

B．引用完整性

C．用户定义的完整性

D．数据完整性

简述保险公司整顿的发生原因。

在同一群落中的不同物种，生态位越接近，竞争越激烈。 ( )

燃烧的三要素是指可燃物、助燃物与点火源。