交易对象是一种权利的交易是( )。 A．现货交易 B．期权交易 C．远期交易

阅读理解。

      No air means death. Though we can't see it, there is air all around us, so air is everywhere and gives life to

every living thing.

      Without it we can't live. Bad air makes people ill. We must have fresh air to keep us in good health.

      In the city there are many people and there are too many cars running on the roads the gas which the cars

spread (传播) out is full of poison (有毒). Every day we breathe it in again and again. This makes us feel sick.

      Besides the cars, there are many factories too. From the chimneys (烟囱) of these factories, we usually get

black and grey smoke. This kind of smoke, when mixed with air, is dangerous to our health because it contains

much poisonous gas. So in order to keep ourselves healthy we should go out to the countryside to breathe more

fresh air.

1. Air is very important because _______. [ ]

A. We can't see it.

B. It is everywhere.

C. It gives life to every living thing.

D. It does no harm to people's health.

2. We must have fresh air to _______. [ ]

A. make our room healthy

B. keep us healthy

C. keep out house clean

D. see every thing clearly

3. The gas which the cars spread out is _______ the black smoke that comes out of the factories. [ ]

A. as grey as

B. as much as

C. as dense as

D. as little as

4. In the city, the air is not so clean as that _______. [ ]

A. in factories

B. out of doors

C. in the countryside

D. indoors

5. We can't get more fresh air when we are in _______. [ ]

A. hills

B. countryside

C. seaside

D. big cities

关于北美的位置，叙述正确的是[ ]

A．美国和加拿大两国领土都有北回归线通过

B．美国和加拿大两国都临北冰洋

C．美国和加拿大两国都有北极圈通过

D．美国和加拿大两国都临墨西哥湾

企业标准体系表具体包括：（）和体系表编制说明等四项内容。

A.标准体系结构图

B.标准明细表

C.统计表

D.标准分类表

经外周静脉左心造影剂的特点是

A．微气泡直径比红细胞大

B．造影剂浓度高

C．微气泡在血中的饱和度大

D．微气泡直径比红细胞小

E．微气泡密度大

MIDI是一种数字音乐的国际标准，MIDI文件存储的__（1）__。它的重要特色是__（2）__。

空白（2）处应选择（）

A.亮度

B.色调

C.色饱和度

D.光强