现代事业制度的核心是（） A.现代事业组织 B.政府组织 C.多样化的组织模式 D.

印版的静态保护包括哪些内容？

血供丰富的肝转移癌多表现为

A．供血血管增粗

B．动静脉瘘

C．病理血管

D．肿瘤染色

E．血管受压弯曲

A．c(H^＋)随着温度的升高而降低

B．在35℃时，c(H^＋)＞c(OH^－)

C．水的电离度α(25℃)＞α(35℃)

D．水的电离是吸热的

气管内一次吸痰时间应限制在（）

A.2秒以内

B.5秒以内

C.10秒以内

D.20秒以内

E.30秒以内

Until recently, most population growth has occurred in relatively dense urban environments. In (91) words, even if we were witnessing rapid population growth, that would not mean that the (92) were filling in with people. (93) , the urban areas would tend to become more crowded. Historically, we find that people have moved to (94) the jobs were. Jobs were usually in ports or locations with many natural (95) . After transportation became relatively cheap, other geographical locations became (96) of economic activity. One factor that determines where people will move to, even when transportation becomes cheap, is (97) . And individuals working in cities (98) higher incomes than those working in (99) areas. Hence, population has tended until the 1970s to (100) in our major urban centers. Recently population has (101) out of the Northeast to the South and to the West for the more pleasant climates. If people did not (102) from living in large cities, there would likely be a much more even population distribution (103) our entire land area. Probably, if this (104) the case, there would be less concern over population (105) Indeed, one need only (106) a cross-country drive or plane trip to realize how (107) populated these United States really are. This is not to say that we should or should not do something about (108) growth. The shortage of people in certain areas merely demonstrates that overpopulation in the United States is really only a problem in (109) urban environments. And this problem may be slowly correcting (110) .

A．vanished

B．drifted

C．shifted

D．escaped