在一个使用ChineseWall模型建立访问控制的信息系统中，数据W和数据X在一个利益冲突类中，数据Y和数据Z在另一个利益冲突类中，那么可以确定一个新注册的用户
Bell-LaPadula模型的出发点是维护系统的___，而Biba模型与Bell-LaPadula模型完全对立，它修正了Bell-LaPadula模型所忽略的信息的___问题。它们存在共同的缺点：直接绑定主体与客体，授权工作困难。
The old man lives in a village_______, but he never feels________.
My mother was determined to help those in need and she would have been immensely proud of what has been achieved these last 20 years. The italicized part in the sentence expresses _______.
Last March the __________ of a 19th century cargo ship was found by an underwater archaeological team.
—Have you finished the work?
—Not yet, but no matter how hard it is, we'll keep ___ until we make it.
Animal mothers are devoted to their young and____ them with love and discipline.
It’s necessary ______ us to keep our pets clean everyday.
He concluded his speech with a remark that failure ____the mother of success.
That radio company is so big that it has a lot of ____ in foreign countries.
—Can you take the day off tomorrow ?
—Well， I‘all have to get（）from my boss.
.If you have really been studying English for so long, it’s about time you _____ able to write letters in English.