2. 15岁男孩，左小腿上段进行性疼痛3个多月，偶有轻微发热。

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问题单项选择题

2. 15岁男孩，左小腿上段进行性疼痛3个多月，偶有轻微发热。体检：左小腿上段外侧方可及一质硬包块，有轻度压痛。左下肢X线片示：左侧腓骨骨干边界模糊，存在不规则破坏区，周围伴“葱皮样”反应。

（2）如果经活组织检查证实为Ewing肉瘤，则最可能来源于: （）

A．成骨细胞

B．破骨细胞

C．骨髓细胞

D．成纤维细胞

答案

参考答案：C

填空题

用所给单词的适当形式填空。

1. It is raining ______ (heavy), I couldn't go out.

2. We enjoyed ______ (oneself) last Sunday.

3. We are excited ______ (see) each other.

4. The old man is very ______ (friend) to me.

5. Look, the sun is shining ______ (bright).

6. —Let's go ______ (skate). —Good idea.

7. Monday is the ______ (two) day of a week.

8. I ______ (can) ride a bike when I was six years old.

9. My brother fell off the bike yesterday and hurt ______ (he).

10. ______ (run) in the morning is good for you.

多项选择题

多元化企业的特点是（）。

A.资源利用率提高

B.增加管理难度

C.共担风险，共负盈亏

D.适应市场变化能力差

E.独立核算