你所知道杂交选育新品种之外，杂交的另一个结果是获得（） A.纯种 B.染色体变异 C

阅读理解。

     MSG (monosodium glutamate) is a food additive (食品添加剂), which has been widely used by many

food factories all over the world since it appeared first in Japan in 1909.

     MSG is a substance that is added to some food to improve its original (原先的) taste and colour. It is

used in foods around the world such as cakes, bread, frozen meats, fish and vegetables. In the beginning,

people thought MSG was safe just like salt and sugar. However, in 1968 some people reported they seemed

to have bad reactions (反应) to MSG after having had a meal at a restaurant. They included headaches and

quick heartbeat (心跳). It was also reported that MSG excited a person's brain and caused his death in Japan.

Scientists think that MSG may lead to many neurological disorders (神经紊乱). In mice studies done by a

university, the evidence showed the mice didn't want to eat the food including MSG.

     Today many food companies"hide" MSG on food labels (标签) by using different names. If you see

"natural flavorings", "hydrolyzed protein" and "spices" in a food label, you are probably seeing a hidden way

to "report" MSG in a food label. Every time we have a meal in a restaurant, we always feel the food very

delicious to taste, but sometimes it is dangerous for our health because some poisonous food additives have

been added to the food.

     To protect people's health, our governments, from central to local, are taking actions to stop factories

producing poisonous food additives.

1. Monosodium Glutamate is _______.

A. a food

B. an additive

C. a factory

D. a country

2. MSG is often used in _______.

A. frozen meats

B. cups

C. clothes

D. book covers

3. The examples in the second paragraph tell us ________.

A. the food including MSG is delicious

B. people like to eat in a restaurant

C. mice like eating the food including MSG

D. MSG is not safe sometimes

4. If you see "natural flavorings", "hydrolyzed protein" and "spices" in a food label, you will know—________.

A. you must eat the food in a hidden way

B. the food label must be hidden

C. MSG is probably added to the food

D. you must report the food to your parents

5. The underlined word "substance" in the article means __________.

A. colour

B. material

C. taste

D. food

在思想品德课上，张华在讲话，同桌李明提醒他注意听讲，老师却误以为是李明违反课堂纪律，严厉地批评了李明。李明觉得很委屈，以下李明的做法正确的是（  ）

A．记在心中，以后上课故意与老师作对

B．选择恰当的时机，主动找老师解释清楚

C．有意疏远老师，避免发生冲突

D．让张华去向老师说明情况

阅读下面的文字，完成文后五题。

人们对碳正离子进行研究时发现，它的“寿命”非常短，大约在10^-23～10^-6秒之间，因此，不能直接用仪器观测到这个有机反应中重要的中间体的“面目”。

欧拉的贡献在于他发现了制备“长寿”高浓度碳正离子的方法。他采用了亲和能力小的溶剂，在低温(大约-100℃)下，可以使碳正离子具有长寿命。为了得到高浓度的碳正离子，欧拉使用一种很强的酸(被称为路易斯酸)，它可以使卤代烷生成碳正离子。

欧拉的成就是建立在许多科学家辛勤工作的基础之上的。早在20世纪50年代，温斯坦在研究亲和取代反应和一些有机物重排时曾经假设，中间体碳正离子是非经典的，它包含一个5配位价的碳。1979年的诺贝尔化学奖获得者布朗对此也做过研究。但是这些仅是假设和解释而已。欧拉的大量工作证明了在强酸介质中，饱和碳氢化合物会发生质子化。

通过对碳正离子的分析，能够发现低成本制造化工产品的方法，目前已有几十种产品得益于欧拉的发现。

文中对欧拉的发现至关重要的一项是（）。

①发现了中间体碳正离子是非经典的。

②发现了碳正离子保持稳定的酸浓度。

③证明在强酸介质中，饱和碳氢化合物会质子化。

④发现碳正离子包含一个5配位价的碳。

A．①③

B．②④

C．②③

D．①④

王安石认为“公私常以困穷为患者，殆以理财未得其道”，下列变法措施中，与解决这一问题有关的是①青苗法②募役法③将兵法④市易法

A．②③④

B．①②③

C．①③④

D．①②④

食品中砷的检测选用（）。

A、分光光度计

B、气相色谱仪

C、液相色谱仪

D、原子荧光光度计