功率因数就是有功功率和视在功率的（）.

下列分子中，含有极性共价键的是（　　）

A．H₂O

B．Cl₂

C．NaCl

D．Na₂O

通过编制工程进度曲线，可获取的信息不包括( )

A．工程量完成情况
B．实际工程进度速度
C．关键工作
D．进度超前或拖延的时间

罗杰斯认为，心理健康的人具有“对经验的开放性”，“无条件的自我关注”，，“机体估价过程”，“与他人和睦相处”和（）5个特征。

A、社会功能的完整性

B、心理与生理的一致性

C、主观与客观的统一性

D、协调的自我

下列无症状细菌尿患者中，不需要治疗的是（）

A.老年人

B.学龄前儿童

C.妊娠妇女

D.肾移植者

E.有尿路梗阻者

The following two questions are based on the following passage:

A study by a group of dentists has concluded that regular use of a certain brand of mouthwash is as effective as flossing in preventing gum disease. The mouthwash company has released a television ad suggesting that people who do not like flossing can now rely solely on mouthwash and brushing to maintain good dental health. A leading manufacturer of dental floss brought a lawsuit against the mouthwash company demanding that the advertisement be discontinued on the grounds that it is misleading.

Which of the following, if true, provides the pest support for the dental floss company’s claim that the advertisement is misleading ？（）

A. The dental floss manufacturer is concerned that it will lose market share in the dental health market because the advertisement encourages people to switch from dental floss to mouthwash.

B. The dental floss company claims in its own advertisements that brushing and flossing after every meal is the most effective way to maintain good dental health.

C. Although mouthwash is an effective deterrent to gum disease, it is less effective than dental floss at removing plaque and preventing cavities between teeth.

D. Per usage, mouthwash is three times more expensive than dental floss, if the recommended amounts of both products are used.

E. The dentists who conducted the study on the effectiveness of mouthwash in preventing gum disease obtained their funding for the study from a company that manufactures mouthwash.