问题 阅读理解

阅读理解。

     Do you want to improve your memory? Are you struggling to remember names and faces as you get

older? Try picking up the phone and speaking to someone. Scientists have found that holding a simple

conversation could be just as effective as playing popular "brain-training" games that have reproduced a

multi-million pound industry.

     Researchers compared 36 studies on memory exercises performed between 1970 and 2007. Some

studies suggested both healthy older adults and those with mild cognitive impairment (轻度认知缺陷)

could remember words better after some memory training.

However, other studies found this improvement was matched by those who were asked to hold a

discussion about art.

     The finding that social interaction could be just as effective at keeping memory loss from getting worse

comes after Age Concern warned more than a million people aged over 65 living alone in their own

homes. The charity warned solitary lifestyles were a 'silent disease' spreading through the nation quickly.

     Dr. Martin said most people experienced a cognitive decline (下降) in old age. This can include

memory loss and inability to plan, pay close attention or perform tasks as quickly as before. The normal

rate of decline seems to speed up in some people, leading to a condition called mild cognitive impairment, which some researchers see as a reason for developing mental diseases later in life.

     Although several studies have suggested that brain-training exercises could delay signs of cognitive

decline, the studies and the types of training have many different kinds. The findings do not mean that

longer, more intense or different exercises might not be effective, but that those which have been reported

thus far have only limited effect.

     Dr. Martin concluded researchers needed to improve the way they used their studies to eventually

determine ways of preventing cognitive decline in old age.

1. What's the main idea of Paragraph 1?

A. People should play more "brain-training" games.

B. Training has a great effect on our health.

C. Having conversation can improve memory.

D. People have no ways to improve memory.

2. What does the underlined word "solitary" probably mean?

A. Unhealthy.

B. Alone.

C. Lacking patience.

D. Enjoying being old.

3.  Mild cognitive impairment can cause people to _______.

A. have mental diseases

B. develop physical diseases

C. worry about the coming of old age

D. escape from the reality in life

4. What message can be implied in the passage?

A. Most people suffer from memory loss.

B. There are more social problems to be settled at present.

C. No one can prevent old age from coming.

D. Whether "brain-training" exercises have a great effect on memory is not sure.

5. The passage would be of great help to ______.

A. children

B. housewives

C. elderly people

D. bad-tempered people

答案

1-5: CBADC

论述题
填空题

甲酸钙广泛用于食品、化工、石油等工业生产上,300~400℃左右分解。Ⅰ、实验室制取的方法之一是:Ca(OH)2 +2HCHO + H2O2 = Ca(HCOO)2 + 2H2O + H2↑。

实验室制取时,将工业用氢氧化钙和甲醛依次加入到质量分数为30-70%的过氧化氢溶液中(投料物质的量之比依次为1∶2∶1.2),最终可得到质量分数98%以上且重金属含量极低的优质产品。

(1)过氧化氢比理论用量稍多,其目的是               

(2)反应温度最好控制在30-70℃之间,温度不易过高,其主要原因是               

(3)制备时在混合溶液中要加入微量硼酸钠抑制甲醛发生副反应外,还要加入少量的Na2S溶液,加硫化钠的目的是               

(4)实验时需强力搅拌45min,其目的是               ;结束后需调节溶液的pH 7~8,其目的是               。最后经结晶分离、干燥得产品。

Ⅱ、某研究性学习小组用工业碳酸钙(主要成分为CaCO3;杂质为:Al2O3、FeCO3) 为原料,先制备无机钙盐,再与甲酸钠溶液混合制取甲酸钙。结合如图几种物质的溶解度曲线及表中相关金属离子生成氢氧化物沉淀的pH(开始沉淀的pH按金属离子浓度为1.0 mol·L-1计算),现提供的试剂有:a.甲酸钠,b.5mol·L-1硝酸,c. 5mol·L-1盐酸,d. 5mol·L-1硫酸,e. 3%H2O2溶液,f.澄清石灰水。

请补充完整由碳酸钙制备甲酸钙的实验步骤

金属

离子

开始沉淀

的pH

沉淀完全

的pH

Fe31. 13. 2
Al33. 05. 0
Fe25. 88. 8
 

步骤1.称取13.6g甲酸钠溶于约20mL水,配成溶待用,并称取研细的碳酸钙样品10g待用。

步骤2.               

步骤3.               

步骤4.过滤后,将滤液与甲酸钠溶液混合,调整溶液pH 7~8,充分搅拌,所得溶液经蒸发浓缩、                  、洗涤、60℃时干燥得甲酸钙晶体。