抖擞dǒu sǒu

A.{t|R(t)∨┐s(t)}

B.{t|R(t)∧┐S(t)}

C.{t|(u)R(t∨┐S(u))

D.{t|(u)R(t)∧┐S(u)}

A、(R(v)∨P(v))∧S(u，v)

B、S(u，v)

C、(R(v)∨P(v))

D、R(v)

A、ωs=Vsu

B、ωs=Vsρ

C、ωs=Vs/ρ

D、ωs=Vs/u

A.P，S，T，U

B.U，T，S，P

C.S，U，P，T

D.P，U，S，T

E.S，P，U，T

F.S，P，T，U

设有关系R、S和T如下图所示，则元组演算表达式{t|(u)((R(u)∨S(u))∧(v)(T(v)→(w)((R(w)∨S(w))∧W[1]=u[1]∧W[2]=∨[1]∧W[3]=∨[2])∧t[1]=u[l])}的运算结果是(48)。

A．

B．

C．

D．

美国药典是（ ）

A．Ph.Int

B．J.P

C．U.S.S.P

D．U.S.P

E．Ch.p

听力原文：If a U.S. company wants to purchase goods in Britain and the transaction is settled in sterling pounds, it has to exchange dollars for pounds first.

(9)

A．The U.S. company has to exchange dollars for pounds to make settlement for the goods imported from U.K.

B．The U.S. company must exchange some pounds for dollars before the transaction is made.

C．The U.S. company may directly purchase goods in Britain in sterling pounds.

D．The U.S. company must exchange dollars for euros first.

A major difference between the Japanese and U.S workforces is that __________.

[A] the Japanese workforce is better disciplined

[B] the Japanese workforce is more productive

[C]the U.S workforce has a better education

[D] ]the U.S workforce is more organize

关系R.S如下表所示，元组演算表达式T={t|R（t）^?u（S（u）→[3]>u[1]运算的结果为（）。