血站对献血者每次采集血液量一般为200～400mL，两次采集间隔期不少于3个月。

[问答题]Most U.S. businesses, large or small, belong to what is called the private enterprise system. 1)This means simply that firms operate in a dynamic environment where success or failure is determined by how well they match and counter the offerings of competitors. Competition is the battle among businesses for consumer acceptance. 2)Sales and profits are the yardsticks by which such acceptance is measured.3)The business world has abundant examples of firms that were once successful but that failed to continue satisfying consumer demands.Competition assures that, over the long run, firms that satisfy consumer demands will be successful and those that do not will be replaced.　　The private enterprise system requires that firms continually adjust their strategies, product offerings, service standards, operating procedures, and the like. 4)Otherwise the competition will gain higher shares of an industry’s sales and profits.Consider the following cases. A & P was long the largest supermarket chain. Now Safeway is the largest, and A & P is attempting a recovery. Ford once was the dominant automaker. Today, it is second to General Motors, among domestic producers. These events suggest the dynamic environment of the private enterprise system.　　5)Competition is a critical mechanism for guaranteeing that the private enterprise system will continue to provide the goods and services that make for high living standards and sophisticated life styles.Few organizations that offer a product or service can escape the influence of competition. The American Cancer Society competes for contributions with the American Heart Association, your own college, and other nonprofit enterprises. The armed forces compete in the labor market with private employers. Even the U.S. Postal Service faces competition. United Parcel Service competes for package shipments. Express Mail faces competition from Western Union’s mailgrams. And firms like The Mailbox, which rents post office boxes in the Seattle area, compete for the post-office-box business.

[单选题]倒装疑问句中间有停顿时应使用（）。

[单选题]下列规范性文件中，属于部门规章的是(    )。

[判断题]冲洗甲板时，一般配备2人，分工要明确，配合要默契。

[判断题]根据我国《保险法》的规定，外国保险机构在中华人民共和国境内设立代表机构，应当经国务院保险监督管理机构批准。

[多选题]房地产开发项目施工招标，需准备的招标文件有＿＿＿＿＿。

[判断题]道岔表示灯用的电源JF，是不经过其他条件的。

[单选题]囊尾蚴病治疗的首选药物是（）

[单选题]vWF的主要作用是（）

[单选题]结核分枝杆菌侵犯肠道主要是（）