供电企业应当向申请用电的用户书面答复供电方案，向用户提供供电方案的期限应当符合：自受

过多边形的一个顶点的所有对角线，将这个多边形分成3个三角形，这个多边形的内角和等于（    ）。

股份制企业组织形式中，以( )最为典型。

A．无限责任制
B．有限责任制
C．股份有限责任制
D．两合责任制

X线在医学上利用的原理包括（）

A.利用其穿透性进行X线检查

B.利用其荧光作用进行透视检查

C.利用其摄影作用进行照片检查

D.利用电离作用进行CT扫描

E.利用其生物效应进行肿瘤治疗

In a survey of consumers in an Eastern European nation, respondents were asked two questions about each of 400 famous Western brands: whether or not they recognized the brand name and whether or not they thought the products bearing that name were of high quality. The results of the survey were a rating and corresponding rank order for each brand based on recognition, and a second rating-plus-ranking based on approval. The brands ranked in the top 27 for recognition were those actually available in the nation. The approval rankings of these 27 brands often differed sharply from their recognition rankings. By contrast, most of the other brands had ratings, and thus rankings, that were essentially the same for recognition as for approval.
Which one of the following, if each is a principle about consumer surveys, is violated by the survey described

A．Never ask all respondents a question if it cannot reasonably be answered by respondents who make a particular response to another question in the same survey.

B．Never ask a question that is likely to generate a large variety of responses that are difficult to group into a manageable number of categories.

C．Never ask all respondents a question that respondents cannot answer without giving up their anonymity.

D．It is better to ask the same question about ten different products than to ask ten different questions about a single product.

E．(E) It is best to ask questions that a respondent can answer without fear of having gotten the answer wrong.

传动要求速度不高、承载能力较太的场合常应用的从动件形式为（）。

A.尖顶式

B.滚子式

C.平底式

D.曲面式