在超过1.5m深的基坑内作业时，向坑外抛掷土石应防止土石（）坑内，并做好临边防护措施

补充词语。

  上（   ）受（   ）         故（   ）重（   ）

（   ）而走（   ）         （   ）急如（   ）

  花（   ）年华               头（   ）眼花

（   ）声（   ）色         （   ）底（   ）渊

党组必须服从谁的领导？

American Museum of Natural History is one of the largest natural and historic museums in the world and one of the main natural history research and education centres in the United States, set up in 1869 and located in the west of the Central Park, Manhattan District, New York. It (1) 7 hectares in its total area, (2) classical types of buildings. The (3) of ancient creatures and humanity is (4) the first place of all the museums in the world, (5) the representative samples from South America, Africa, Europe, Asia and Australia were collected, besides those from the (6) country, the United States.

In the museum, there are five kinds of exhibits, including astronomy, mineralogy, human history, and animals in the (7) times and those in modern times. There are thirty-eight exhibition halls with different (8) from 500 to 1,500 square metres. Besides these, there is a Roosevelt Memorial Hall in (9) of President Roosevelt who supported the (10) of the museum, which is also used to have a special exhibition, showing the new important (11) on natural sciences and (12) affairs and social problems, and special topics connected closely with the life of the citizens. Besides this, it is also used for avocation (13) to have all kinds of scientific activities in the laboratories, centres of natural science and centres for citizens. There are more than 10 (14) research departments mainly (15) for collection of samples, research and work of publication.

In the museum, there are (16) and sub-libraries of Aulspond ancient amniote, with about 300 thousand books and magazines (17) natural history, many of (18) are very valuable monographs for the first edition. It has published many expert books and magazines, and a large number of propaganda materials, (19) which are the two magazines, Natural History and Members of Museum that have the biggest (20) of their magazines.

15（）

A.evident

B.reliable

C.responsible

D.excessive

（）是渐进镜的优点。

A、看中距与看过清晰

B、全和的清晰视力

C、看远与看中距离均能看清

D、看远与看近均能看清

项目管理的核心任务是项目的（）。

A.组织协调

B.目标控制

C.合同管理

D.风险管理