问题 多项选择题

某投资者以65000元/吨卖出一手8月铜期货合约,同时以63000元/吨买入一手10月铜合约,当8月和10月合约价差为()元/吨时,该投资者获利。

A.1000

B.1500

C.-300

D.2000

答案

参考答案:A, B, C

解析:此时期货合约远期价差为65000-63000=2000元/吨,只要8月和10月合约价差小于2000元/吨,该投资者均获利,所以A、B、C选项正确。

阅读理解

阅读理解。

     Studying for an exam while listening to music is not smart, because background music can injure

your ability to perform memory tasks, new research has found.

     Study participants were asked to recall a list of eight consonants (辅音字母) in the order they

were presented. They did this while in five different sound environments: quiet surroundings; music

they liked music they disliked; changing state; and steady state.

     The participants recall ability was poorest when listening to music, regardless of whether

they liked or disliked it, and in changing-state conditions. The most accurate recall occurred

     when participants performed the task in steady-state environments, according to the study

published online in the journal Applied Cognitive Psychology.

     The poorer performance of the music and changing-state sounds are due to the audible (听得

见的) change within those environments. This hurts the ability to recall the order of items, via retelling,

within the presented list, explained lead researcher Nick Perham, a lecturer in the School of Psychology

at the University of Wales Institute in Cardiff, in a news release from the journal's publisher.

      "Mental arithmetic (算术) also requires the ability to memorize order information in the short-term

via retelling, and may be similarly affected by their performance in the presence of changing-state,

background environments," he added.

1 When performing a challenging mental task, you'd better do it ______.

A. in the music you like                

B. in the music you dislike

C. in changing state                    

D. in steady state

2. The reason why the participants performed poorly while listening to music is that ______.

A. the music was too loud

B. they got lost in the music

C. the changeable sound disturb the input of the information

D. they couldn't focus their attention

3. Which of the following is in steady state?

A. 12345.        

B. 33333.

C. abcde.          

D. a1b2c.

4. We can learn from the text that ______.

A. When doing our homework, we'd better play sweet songs

B. Music may affect our performance of memorizing

C. Mental arithmetic means retelling the order of information

D. Reading in the noisy street can strengthen our ability of concentrating

单项选择题