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【单选题】
设有关系R、S和T如下图所示，则演算表达式{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.
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反馈参考答案：
举一反三
【简答题】把单位时间内通过某一导体横截面的电荷量定义为 (简称电流),用 来表示。
【简答题】A．The Moon has no water B．The Moon's materials came from Earth's core C．The Moon's core differs from its suce D．The Moon contains little iron
【单选题】The moon , we came to the foot of the mountain.
A.
appeared
B.
appears
C.
appearing
D.
have appeared
【单选题】When should the man pay the fees?
A.
Within 24 hours of registering.
B.
One week before the designated registration date.
C.
24 hours before the registration date.
D.
After he gets a letter from university financial officer.
【简答题】什么是产品标识？产品标识的目的是什么？
【简答题】铸工造型时严格禁止 型砂,以免迷住眼睛。
【单选题】In the first 24 hours after abandoning a vessel, water should be given only to personnel who are ______.
A.
sick or injured
B.
wet
C.
Awake
D.
thirsty
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