一段钢材，横截面是边长1分米的正方形，这段钢材的表面积是42平方分米，它的长是_

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       Mr Green is a teacher.He teaches English in No.1 Middle School.He works hard.Mrs.Green stays

at home.She doesn't go to work every day.She does the housework very well.Their son,Billy is nine.Billy

likes playing and doesn't like learning.He can't do his homework and often asks his mother to help him.

But Mrs Green can't do it,either.She asks Mr.Green to do all the homework for Billy every day.Mrs Green says she does some housework when he helps their son.

1. Mr Green is            teacher.

A. English

B. a Chinese

C. American

D. an English

2. Mrs Green is a            .

A. teacher

B. worker

C. housewife

D. student

3. Their son is            years old.

A. seven

B. eight

C. nine

D. ten

4. Billy doesn't like            .

A. playing

B. cooking

C. studying

D. doing

5.            does the homework.

A. Billy

B. Mr Green

C. Mrs Green

D. his teacher

下面是进行探究活动要遵循的一般步骤，按照先后顺序排列正确的是

①实施计划②作出假设③制定计划④得出结论⑤提出问题⑥表达和交流。

A．⑤②③①④⑥

B．①③④⑤②⑥

C．⑤④③②①⑥

D．②③④①⑤⑥

病历摘要：患者男性，23岁，双眼视力下降三年，不伴有红、肿及眼痛症状，夜间视力下降更为明显，曾在当地医院作过治疗，具体用药不详，但无明显疗效。家族中无明显类似病者，父母非近亲结婚。否认有眼外伤、中毒与传染病史。

视网膜色素变性不典型表现包含？（）

A.无色素性视网膜色素变性

B.有出血型视网膜色素变性

C.有渗出型视网膜色素变性

D.单侧性视网膜色素变性

E.双侧性视网膜色素变性

F.象限性视网膜色素变性

G.上下不全型视网膜色素变性

H.中心性或旁中心性视网膜色素变性

气水同产井在开采过程中受地层水的干拢（）。

A.无干拢

B.不明显

C.明显

D.以上都不对

患者经行前后，大便泄泻，经色淡，质清稀；腰膝酸软，头晕耳鸣，畏寒肢冷；舌淡，苔白，脉沉迟。治疗应首选的方剂是（）

A.参苓白术散

B.八珍散

C.补中益气汤

D.四神丸合健同汤

E.左归丸