[单项选择]

Simulation

A chosen B played C assigned D divided

[单项选择]A. He is afraid he won’t be chosen.
B. The boss hasn’t decided where to go.
C. Such a trip is necessary for the company.
D. It’s not sure whether there is a trip.

[填空题]

A．asked
B．missed
C．whipped
D．played

[单项选择]A. They have already chosen a president.
B. They will choose a president in a few months.
C. She thinks earlier reports that they chose a new president were false.
D. She thinks the appointment will take effect soon.

[单项选择]A) I played the basketball yesterday. C) Do you like it
B) Thank you. D) That’s right.

[单项选择]设关系R：

A	B	C
a	b	c
d	c	c
c	b	d

经操作Л_A，B(σC=’c’(R))的运算结果是( )。(Л为“投影”操作符，σ为“选择”操作符)
A.

A	C
a	b
d	c
c	d

[单项选择]A. He was joking with Freud.
B. He played in Freud’s office.
C. He unconsciously revealed his intention of refusing to pay.
D. He only made his empty promise to Freud.

[单项选择]Where did the children played

[单项选择]有三个关系R、S和T如下：

R
B	C	D
a	0	k1
b	1	n1

S
B	C	D
f	3	h2
a	0	k1
n	2	x1

T
B	C	D
a	0	k1

由关
A. 并
B. 自然连接
C. 笛卡儿积
D. 交

[单项选择]Most animals are chosen for（）
A. their personality
B. their ability to be trained
C. their appearance
D. their friendliness

[单项选择]有A、B、C三种投资产品，其收益的相关系数如下：

	A	B	C
A	1
B	0.1	1
C	0.8	-0.8	1

若必须选择两个产品构建组
A. B、C组合是风险最佳对冲组合
B. A、C组合风险最小
C. A、B组合风险最小
D. A、C组合风险最分散

[单项选择]设有如下关系表：

R
A	B	C
1	1	2
2	2	3

S
A	B	C
3	1	3

T
A	B	C
1	1	2
2	2	3
3	1	3

则下列操作中正确的是______。
A. T=R∩S
B. T=R∪S
C. T=R×S
D. T=R/S

[单项选择] Whatever their chosen method, Americans bathe zealously. A study conducted found that we take an average of 4.5 baths and 7.5 showers each week and in the ranks of non edible items purchased by store customers, bar soap ranks second, right after toilet paper. We spend more than $ 700 million annually on soaps, but all work the same way. Soap is composed of molecules that at one end attract water and at the other end attract oil and dirt, while repelling water. With a kind of pushing and pulling action, the soap loosens the bonds holding dirt to the skin. Unless you’’re using a germicidal soap, it usually doesn’’t kill the bacteria soap simply removes bacteria along with dirt and oil. Neither baths nor showers are all that necessary and unless you’’re in a Third World country where infectious diseases are common, or you have open sores on your skin, the dirt and bacteria aren’’t going to hurt. The only reason for showering or bathing is to feel clean and refreshed. There is a phy
A. you use a germicidal soap
B. use an anti-bacterial soap
C. you use soap to scrub it vigorously
D. you are under special treatment for it