釉质呈淡黄色的原因是由于（） A.釉质钙化不良 B.釉质缺损 C.釉质本身的颜色 D

阅读理解。

     Everybody can suffer＊ from stress. No matter what your age is, you can feel stressed out by things

that are happening in your life. Teenagers, however, have many more opportunities＊ to get stressed than

people in any other age group. Being a teenager is hard. You are not a child any more, but you are not an

adult, even though you have to deal with some grown-up problems and decisions. Families can be one of

the biggest causes of stress, such as arguing with parents at home, or with brothers and sisters. Teenagers

also have a lot of stress from school, either from their teachers or from their friends. Some teenagers also

feel stressed about choosing their education after high school. Getting a place at a good university can be

very difficult and some cannot afford to go to university. The stress about getting a job when finishing

school is hard for some teenagers. There are so many young people finishing school and not enough jobs

for them. Sadly, there is nothing we can do to remove＊ these causes of stress from the lives of teenagers,

but you can learn the best way to deal with it. Talking to people is one of the best ways to deal with stress. It

may sound simple, but it is true. A problem shared is a problem halved＊.

1. Why is being a teenager often difficult?

A. Because even though you are not an adult, you must deal with grown-up problems.

B. Because even though you are an adult, you must deal with children's problems.

C. Because even though you are a teenager, you must do a lot of homework.

D. Because adults often make them feel stressed.

2. Families can add to the stress a teenager might experience _________.

A. by asking them to go to university

B. by helping them with their homework

C. as teenagers argue with their parents, their brothers or sisters

D. as families never support＊ their children enough

3. Why can leaving high school be a stressful time for teenagers?

A. Because they will be leaving their favorite teachers.

B. Because many people's favorite memories are at school.

C. Because they may worry about getting a place at university.

D. Because they may worry about becoming an adult.

4. We can deal with the stress in our life _________.

A. by not trying to find a job

B. by forgetting about our problems

C. by getting a place at university

D. by sharing our problems with our friends

女孩5岁，发热1个月、伴两下肢疼痛1周入院。卡介苗按时接种，否认结核接触史。体检：体温38．5℃，稍苍白，下肢有少许散在出血点，浅淋巴结易及，如绿豆及黄豆大，咽充血，心、肺无异常，腹软，肝肋下2cm，脾不肿大，两下肢无明显关节红肿，检查时稍感胀痛，神经系统无特殊。血红蛋白98s／L，白细胞数12×10⁹／L，中性粒细胞0．30，淋巴细胞0．70，血沉48mm／h，骨髓穿刺证实为急性淋巴细胞白血病。

本例按上述资料，应属下列哪一型（）

A.L1型、标危型

B.L2型、高危型

C.L1型、高危型

D.L2型、高危型

E.L2型、标危型

朱红的论证是通过以下哪种方式展开的

A．陈述了一个一般规律，该论证是运用这个规律的一个实例。

B．对更大范围的一部分可观察行为做出了描述。

C．根据被清楚理解的现象和未被解释的现象间的相似性进行类推。

D．排除对一个被观察现象的一种解释，得出了另一种可能的解释。

清洗后的餐具可用多大浓度的过氧乙酸浸泡5～10分钟，就可消毒（）

A.100mg／L

B.200mg/L

C.300mg/L

D.400mg/L

E.500mg/L

在一间宾馆的一层的同一侧恰好连续并排着七所房间(A—7)，每所房间住着一个房客。这七个房客是：韩国人，英国人，美国人，日本人，德国人，法国人，瑞典人．七个房客由l一7排列符合下列条件：瑞典人不住在这排房间的l号，也不住在这间宾馆的7号韩国人住在C号；美国人与韩国人相邻；法国人住在韩国人的房间号大于美国人，并且小于英国人

如果德国人的房问号大于美国人，那么以下哪一项必然是真的

A．韩国人房间号大于美国人

B．韩国人房间号小于瑞典人

C．德国人房间号小于法国人

D．德国人房间号小于英国人