世界上200多个国家和地区,能够独立研制并发射人造卫星的国家只有()家。
A.6
B.7
C.8
D.9
参考答案:D
在下列药物中不属于第三代喹诺酮类抗菌药物的是
A.依诺沙星B.西诺沙星C.诺氟沙星D.洛美沙星E.氧氟沙星
In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.
It is more and more usual that users of Information Retrieval (IR) systems must face up to response of hundreds or thousands of (1) documents. A significant proportion of them are moreover (2) or redundant. This is a straight consequence of two well - known facts: the incessant growing of documental databases and the lack of ability of most users to define (3) information needs. In such a framework, further effective retrieval techniques are only part of the solution. Interfaces with alternative ways for organizing and (4) the results returned by a (5) would be of great utility assisting users to find relevant documents. Document clustering may play a central role as an effective technique for organizing query results.
3()
A.concrete
B.special
C.specific
D.particular