【单选题】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)。
【单选题】What is the website of booking tickets online?
A.
It is http://www.12306.cn/.
B.
It is http://www. chinadaily.cn/.
C.
It is http://www. baidu.cn/.
D.
It is http://www. alibaba.cn/.
【单选题】What is the main idea of the website?
A.
which types of cargo fit different boxcars
B.
the safety features of the company’s boxcars
C.
the types of boxcars a company carries
D.
ways to reduce freight costs by using boxcars
【单选题】What is the aim of the website, wildlifedirect.org?
A.
To let tourists book holidays to see endangered species.
B.
To let people know how to do volunteer work.
C.
To let conservationists share information about their work.
【单选题】What is the main idea of the website?
A.
Which types of cargo fit different boxcars
B.
The safety features of the company's boxcars
C.
The types of boxcars a company carries
D.
Ways to reduce freight costs by using boxcars
【单选题】下列应用中,使用人工输入方法的是( )。
【单选题】下列应用中,使用人工输入方法的是__(2014)
【单选题】A:会議は始まりましたか。B:まだです。それでは会議を( )。