[单项选择]
{{B}}End Your Back
Pain{{/B}}
Like an expensive but temperamental sports car, the
human spin is beautifully designed and maddeningly unreliable. If you are a
living, breathing human being, you have probably suffered the agony of back
pain. And as long as people continue to lead overweight, sedentary and stressful
lives, the number of sufferers is unlikely to go anywhere other than
up.
As it does, armies of new back-pain sufferers, many
desperate and even disabled, will seek relief. When they do, they’ll quickly
discover just how complicated their problem really is, with its mystifying mix
of physical symptoms and psychological underpinnings. The reality is that the
agony will often go away on its own — impossible as that may seem when you are
writhing (痛苦扭曲) on the kitchen floor. The Great Pain Mystery
Back pain can originate anywhere in the elaborate spinal architecture.
A. plain ageing
B. spine defects
C. surgical failures
D. mental stress
[填空题]If I ______ (be) you, I wouldn’t buy that expensive diamond ring.
[填空题]Chiaki Mukai’s mother was against her daughter’s choice because she thought that being an astronaut was dangerous.
[单项选择]有关系模式R(S，T，C，D，G)，根据语义有如下函数依赖集：F=(S，C)→T，C→D，(S，C)→G，T→C。
关系模式R的候选关键码( )。
A. 仅有1个，为(S，C)
B. 仅有1个，为(S，T)
C. 有2个，为(S，C)和(T)
D. 有2个，为(S，C)和(S，T)
[单项选择]设有关系R(A，B，C) 和S(C，D) 。与关系代数表达式πA,B,D(σR.C=S.C(R×S)等价的SQL语句是
A. SELECT*FROM R,S WHERE R.C=S.C
B. SELECT A,B,D FROM R,S WHERE R.C=S.C
C. SELECT A,B,D FROM R,S WHERE R=S
D. SELECT A,B FROM R WHERE(SELECT D FROM S WHERE R.C=S.
