For hundreds of years, pearl divers have g

题型:单项选择题

问题:

For hundreds of years, pearl divers have gathered pearls directly from mollusks on the seafloor. This is an extremely risky profession, exposing the divers to risks of drowning, air embolism, and shark attacks. Still, as long as society demands authentic cultured pearls, these brave divers must continue to risk their lives.
Which of the following statements, if true, most seriously weakens the conclusion above ?()

A. Shark attacks on pearl divers have decreased steadily over the last three decades because of declining shark populations.

B. Cultured pearls are generally considered more beautiful than those made by artificial means.

C. Robotic pearl harvesters can gather pearls faster and at less cost than human divers, although they may disturb aquatic communities.

D. Part of the value of cultured pearls derives from the exotic way in which they are obtained.

E. With the proper equipment and training, a diver employing scuba gear can harvest three times as many pearls per hour as can a free air diver.

考点:在职联考工商(经企)管理硕士入学考试(GMAT)GMAT研究生管理入学考试英语
题型:单项选择题

从含镍废催化剂中可回收镍,其流程如下:

某油脂化工厂的含镍催化剂主要含有Ni,还含有Al(31%)、Fe(1.3%)的单质及氧化物,其他不溶杂质(3.3%).部分阳离子以氢氧化物形式完全沉淀时的pH如下:

沉淀物Al(OH)3Fe(OH)3Fe(OH)2Ni(OH)2
pH5.23.29.79.2
回答下列问题:

(1)“碱浸”的目的是除去______.

(2)“酸浸”时所加入的酸是______(填化学式).酸浸后,滤液②中可能含有的金属离子是______.

(3)“调pH为2~3”的目的是______.

(4)产品晶体中有时会混有少量绿矾(FeSO4•7H2O),可能是由于生产过程中______.

(5)NiSO4在强碱溶液中用NaClO氧化,可制得碱性镍镉电池电极材料--NiOOH.该反应的离子方程式是______.

题型:单项选择题

()是指不分运输距离的远近,只按航线、货物名称或等级制定的运价。

A.等级运价

B.单项费率运价

C.航线运价

D.协议运价

题型:单项选择题

国务院有关部门、设区的市级以上地方人民政府及其有关部门,对其组织编制的工业、农业、水利、交通、旅游等专项规划,应在该规划草案上报前进行环境影响评价,并向审批该专项规划的机关提出( )。

A.环境影响报告表
B.有关环境影响的说明
C.环境影响报告书
D.环境影响登记表

题型:单项选择题

罗茨鼓风机按结构形式分为两转子在同一竖直平面内而气流()的立式结构和两转子在同一水平平面内而气流()卧式结构两类。

A.垂直进、垂直出;水平进、水平出

B.水平进、水平出;垂直进、垂直出

C.水平进、垂直出;垂直进、水平出

D.垂直进、水平出;水平进、垂直出

题型:单项选择题

在完全垄断市场上,厂商面对的需求曲线()

A、与数量轴平行

B、与边际收益曲线重合

C、向右下方倾斜

D、位于边际收益曲线的下方

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