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问题 单项选择题

患者男，38岁，患地中海贫血（纯合子β-地中海贫血），巨脾，腹痛。去年，治疗输血量增加，为进一步治疗欲行脾切除术。脾切除术的益处除减少输血量外，还有（）

A.降低凶险性感染的可能性

B.预防严重血小板增多所致出血并发症

C.减少潜在脾破裂风险

D.减少皮质激素用量

E.预防红细胞结构异常

答案

参考答案：C

单项选择题

Guitar strings often go "dead"—become less responsive and bright in tone—after a few weeks of intense use. A researcher whose son is a classical guitarist hypothesized that dirt and oil, rather than changes in the material properties of the string, were responsible.
Which of the following investigations is most likely to yield significant information that would help to evaluate the researcher’s hypothesis

A．Determining if a metal alloy is used to make the strings used by classical guitarists.

B．Detennining whether classical guitarists make their strings go dead faster than do folk guitarists.

C．Detennining whether identical lengths of string, of the same gauge, go dead at different rates when strung on various brands of guitars.

D．Determining whether a dead string and a new string produce different qualities of sound.

E．(E) Determining whether smearing various substances on new guitar strings causes them to go dead.
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单项选择题

豌豆花的顶生和腋生是一对相对性状，根据下表中的三组杂交实验结果，判断显性性状和纯合子分别为( )。

杂交组合 子代表现型及数量
甲(顶生)×乙(腋生) 101腋生，99顶生
甲(顶生)×丙(腋生) 198腋生，201顶生
甲(顶生)×丁(腋生) 全为腋生

A．顶生；甲、乙
B．腋生；甲、丁
C．顶生；丙、丁
D．腋生；甲、丙
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