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问题 选择题

关于电解水实验的叙述错误的是（　　）

A．试管a中的气体是H2

B．试管b中的气体能使带火星的木条复燃

C．产生的H2和O2的质量比为2：1

D．发生反应的化学方程式为2H2O

 通电 
.
 
2H2↑+O2↑

答案

A、电解水实验中，正极产生氧气，负极产生氢气，如图所示，试管a中的气体是H2，试管b中的气体是O2，故A叙述正确；

B、试管b中的气体是O2，能使带火星的木条复燃．故B叙述正确；

C、产生的H2和O2的体积比为2：1，质量比需有相对分子质量计算．故C叙述不正确；

D、发生反应的化学方程式为2H2O

 通电 
.
 
2H2↑+O2↑，故D叙述正确．

故选C．

单项选择题

The following data sufficiency problems consist of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of counterclockwise), you must indicate whether.

If a＞0 and b＞0, is ？（）

(1) a=b-2

(2) [*]

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.
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单项选择题

患者，男性，72岁。心前区疼痛5小时，心电图检查示急性广泛前壁心肌梗死伴室性早搏。体检：气急不能平卧，血压130/80mmHg，心率120次/分，早搏10次/分，并有奔马律。两肺散在细湿啰音，伴少许哮鸣音。肝颈静脉回流征阴性。

入院后即查血清酶，下列哪种心肌酶在起病后最早升高( )

A．丙氨酸氨基转移酶(ALT)

B．肌酸磷酸激酶(CPK)

C．天门冬氨酸氨基转移酶(AST)

D．碱性磷酸酶(AKP)

E．乳酸脱氢酶(LDH)
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