网络会议文献的检索途径主要有哪些？
参考答案：综合的大型搜索引擎；专业学科搜索引擎；专业学会、协会、科研院所网站；联机数据库中的会议文献；会议文献数据库。
Visitors to this country are normally admitted for six months, but foreign students can usually stay for one year. They must (51) an educational institution, and they are required to study for a minimum of fifteen hours a week on a (52) course. Prospective students have to show that they can afford their studies, and that they have sufficient (53) resources to support themselves (54) in this country.
In order to work here the foreigner needs a work permit, (55) must be applied for by his prospective employer. The problem here is that the Department of Employment has the right to grant or (56) these permits, and there is little that can be done (57) it; it would be extremely unwise for a foreign visitor to work (58) a permit, since anyone doing so is liable to immediate deportation (驱逐出境). There are some people from the Common Market countries, who are often given (59) residence permits of up to five years. Some other people, such as doctors, foreign journalists, authors and others can work without permits, and foreign students are normally allowed to (60) part-time jobs while they are studying here.
58().
A.with
B.before
C.after
D.without
在夜间起步时，开启近光灯、左转向灯，注意观察两侧的车辆和行人，特别要注意提防黑暗中的车辆和行人。
