探测器离开金属物品时，灵敏度恢复恒定频率，此时小喇叭哑点。

酸根离子XO₃^2－所含电子数比碳酸根离子CO₃^2－的电子数多10，则下列说法不正确的是（   ）

A．XO₃^2－中X元素与CO₃^2－中C元素的化合价相同

B．XO₃^2－与CO₃^2－都只能被还原，不能被氧化

C．X和C不是同周期元素，但都属于主族元素

D．XO₃^2－与CO₃^2－都能在溶液中与XO₂反应

古罗马建筑师马可·维特鲁威在《建筑十书》中提出的建筑三要素不包括（）

A、实用

B、坚固

C、美观

D、创新

经营单位（）

A. 广州海关

B. 广东省纺织品进出口针织品有限公司

C. 广州纺织品进出口公司

D. 广东美雅股份有限公司

电子商务是一个以（）为支撑的全球商务活动。

A．办公自动化技术

B．信息技术

C．运输技术

D．仓储技术

Anatomical bilateral symmetry is a common trait. It follows, therefore, that it confers survival advantages on organisms. After all, if bilateral symmetry did not confer such advantages, it would not be common.
The pattern of reasoning in which one of the following arguments is most similar to that in the argument above

A．Since it is Sawyer who is negotiating for the city government, it must be true that the city takes the matter seriously. After all, if Sawyer had not been available, the city would have insisted that the negotiations be deferred.

B．Clearly, no candidate is better qualified for the job than Trumbull. In fact, even to suggest that there might be a more highly qualified candidate seems absurd to those who have seen Trumbull at work.

C．If Powell lacked superior negotiating skills, she would not have been appointed arbitrator in this case. As everyone knows, she is the appointed arbitrator, so her negotiating skills are detractors notwithstanding, bound to be superior.

D．Since Varga was away on vacation at the time, it must have been Rivers who conducted the secret negotiations. Any other scenario makes little sense, for Rivers never does the negotiating unless Varga is unavailable.

E．(E) If Wong is appointed arbitrator, a decision will be reached promptly. Since it would be absurd to appoint anyone other than Wong as arbitrator, a prompt decision can reasonably be expected.