一个由任意数字组成的三位密码,若破解密码者只知道密码中的其中一位是错误的,那么破解改密码需要试验()次。
A、5.0
B、10.0
C、20.0
D、30.0
参考答案:D
患者,女性,70岁,高血压史5年,3个月前右眼突然视力下降,外院诊断为右眼缺血型视网膜中央静脉阻塞,予药物治疗。2天前,患者出现右眼胀痛。检查右眼视力数指,角膜上皮水肿,前房不浅,虹膜红变,晶状体尚透明,眼压40mmHg。
下列哪项不是这类疾病的常见原因()
A.视网膜中央静脉阻塞
B.糖尿病性视网膜病变
C.外层渗出性视网膜病变
D.视网膜中央动脉阻塞
E.白内障
There is virtually no limit to how one can serve community interests, from spending a few hours a week with some charitable organization to practically full-time work for a social agency. Just as there are opportunities for voluntary service (1) (VSO) for young people before they take up full-time employment, (2) there are opportunities for overseas service for (3) technicians in developing countries. Some people, (4) those who retire early, (5) their technical and business skills in countries (6) there is a special need.
So in considering voluntary or (7) community service, there are more opportunities than there (8) were when one first began work. Most voluntary organizations have only a small full-time
(9) and depend very much on volunteers and part-timers. This means that working relationships are different from those in commercial organizations, and values may be different. (10) some ways they may seem more casual and less efficient, but one should not (11) them by commercial criteria. The people who work with them do so for different reasons and with different (12) , both personal and (13) . One should not join them (14) to arm them with professional experience; they must be joined with commitment to the (15) , not business efficiency. Because salaries are (16) or non-existent many voluntary bodies offer modest expense. But many retired people take part in community service for (17) , simply because they enjoy the work.
Many community activities possible (18) retirement were also possible during one’s working life but they are to be undertaken (19) seriously for that. Retired people who are just looking for something different or unusual to do should not consider (20) community service.
17()
A.free
B.freedom
C.money
D.something