通常把原子总数和价电子数相同的分子或离子称为等电子体。人们发现等电子体的空间结构

题型:选择题

问题:

通常把原子总数和价电子数相同的分子或离子称为等电子体。人们发现等电子体的空间结构相同,则下列说法中正确的是(      )

A.CH4和NH4+是等电子体,键角均为60°。

B.NO3- 和CO32-是等电子体,均为平面三角形结构。

C.H3O+和PCl3是等电子体,均为三角锥形。

D.B3N3H6和苯是等电子体,B3N3H6分子中不存在“肩并肩”式重叠的轨道。

考点:构成物质的粒子—分子、原子、离子元素周期律
题型:选择题

下列各项中,属于实践合同的是()。

A.租赁合同

B.赠与合同

C.保管合同

D.买卖合同

题型:选择题

缺铁性贫血最敏感或最可靠的检验方法是()。

A.血清铁降低

B.血清总铁结合力降低

C.红细胞数下降

D.血色素下降

E.血清铁蛋白降低

题型:选择题

It is _______ of the students to stay up reading till late night before the final exam.

A.common

B.typical

C.normal

D.regular

题型:选择题

阅读下面短文并回答问题。

[1] The air we breathe is so freely available that we take it for granted. Yet without it we could not survive more than a few minutes. For the most part, the same air is available to everyone, and everyone needs it. Some people use the air to sustain them while they sit around and feel sorry for themselves. Others breathe in the air and use the energy it provides to make a magnificent life for themselves.

[2] Opportunity is just the same. It is everywhere. Opportunity is so freely available that we take it for granted. Yet opportunity alone is not enough to create success. Opportunity must be seized and acted upon in order to have value. So many people are so anxious to “get in” on a “ground floor opportunity”, as if the opportunity will do all the work. That’s impossible.

[3] Just as                                   , you need opportunity to succeed. It takes more than just breathing in the fresh air of opportunity, however. You must make use of that opportunity.’’ That’s not up to the opportunity. That’s up to you. It doesn’t matter what “floor” the opportunity is on. What matters is what you do with it.   

小题1:What is the main idea of the passage? ( no more than 8 words)

_____________________________________________________________________

小题2:Complete the following statement with proper words. (no more than 6 words)

There are persons who live aimlessly breathing in air and                                         .

小题3:Fill in the blank in the third Paragraph with proper words or phrases to complete the sentence. ( no more than 6 words)

_____________________________________________________________________

小题4:According to the author, how should we use the air? ( no more than 15words)

_____________________________________________________________________

小题5: What does the word “It” (Line 5, Paragraph 3) probably refer to? ( no more than3 words)

_____________________________________________________________________

题型:选择题

男性,18岁。因转移性右下腹痛12h入院,诊断为急性阑尾炎。当晚行阑尾切除术,病理检查系坏疽性阑尾炎。次晨起患者诉腹痛,烦躁不安。检查:面色较苍白,皮肤湿冷,血压80/60mmHg,脉搏110次/分;全腹压痛,轻度肌紧胀,肠鸣音弱。

该患者目前应考虑可能是

A.术后疼痛所致

B.术后肠麻痹

C.术后腹腔内出血

D.粘连性肠梗阻

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