问题 单项选择题

在对数据库的系统故障进行恢复时,需要对日志文件进行:

A. 反向扫描

B. 正向扫描

C. 双向扫描

D. 随机扫描

答案

参考答案:B

解析:系统故障恢复的步骤:正向扫描日志文件,找出在故障发生前已提交的事务,将其事务标识记入REDO队列;找出在故障发生时尚未完成的事务,将其事务标识记入UNDO队列;对UNDO 队列中的事务进行UNDO处理,即反向扫描日志文件,对每一个需要UNDO的事务的更新操作执行逆操作;对REDO队列中的事务进行REDO处理,即正向扫描日志文件,对每一个需要 REDO的事务的更新重新执行日志记录登记的操作。

单项选择题 A1/A2型题
阅读理解

Two worlds come together

Imagine landing in a foreign country where you cannot speak the language, understand the culture and don’t know anybody. Wouldn’t it be nice to have a friend who could help you out?

John Smith, an English explorer who landed in America in 1607, found the best friend ever. She was a Native American named Pocahontas (1595-1617). And she did more than teach Smith the language: she saved his life, twice.   

Smith was captured(捕获) by members of Pocahontas’s tribe (部落) and was going to be killed. But for some reason, the Chief’s daughter, Pocahontas, felt sorry for Smith (who was probably the first white man she had ever seen) and threw her body over his to protect him. Smith returned safely to the small village he was living in.

During the winter the English settlers did not know how to get food from nature. Pocahontas often brought food for Smith and his friends.

A year later Pocahontas’s father tried to kill Smith again because the Native Americans were very scared the English would try to take over their land. Pocahontas warned him and he was able to escape.

Later she became a Christian and eventually married an Englishman named John Rolfe.

She spent the last year of her life in London.

Pocahontas has become an American legend. Her life story has been re-created in many books and films, including Disney’s 1995 film, Pocahontas.

One of the reasons she is so popular is that many Europeans look at Pocahontas as an excellent example of how a minority can adjust into the majority. Pocahontas is also respected because of her selfless love. She proved that people can be kind and loving even to people of a different race or culture. John Smith was very different from Pocahontas but she could see he was a good man and that was all that mattered. No race or country owns goodness, love and loyalty.

小题1: What difficulties might early European settlers meet in America EXCEPT ________?

A.the fierce conflict with Native Americans

B.bad-tempered natives who enjoyed killing

C.unfamiliarity with a foreign land

D.lack of food in winter小题2: Pocahontas saved John Smith twice because ______.

A.he was the first white man she had ever seen in her life

B.she wanted to become a Christian and marry an Englishman

C.she believed in general kindness even to people of a different race

D.she was on the settlers’ side and against her cruel father小题3: According to the text, Europeans think Pocahontas _____.

A.was brave to break away from her own tribe

B.set a good example for other natives to accept the white settlers

C.was a selfless Christian who can love her enemy

D.was open to a more advanced culture小题4: What can we infer from the passage?

A.The battles between early settlers and Native Americans resulted from their fighting for land.

B.The Europeans think the early settlers should have learned to adjust to the local cultures.

C.The creation of America is based on the settlers’ victory over the Native Americans.

D.People from different cultures can never really get along well with each other.