下面哪个不属于选择防病毒软件时应考虑的要素？（）A、技术支持程度 B、技术的先进性和稳

如图所示，小球沿水平面以初速度v₀通过O点进入半径为R的竖直半圆弧轨道，不计一切阻力，下列说法正确的是（　　）

A．球进入竖直半圆弧轨道后做匀速圆周运动

B．若小球能通过半圆弧最高点P，则球运动到P时向心力恰好为零

C．若小球能通过半圆弧最高点P，则小球落地点时的动能为5mgR2

D．若小球恰能通过半圆弧最高点P，则小球落地点O点的水平距离为2R

阅读下面的诗歌，然后回答问题。

        [注]①李弥逊(1085 -1153)，字似之，吴县（今属江苏省苏州市）人，历任中书舍人、户部侍郎等职。因竭力反对秦桧的投降政策而被免职。②张罗地：指门可罗雀、十分冷落的地方。

(1)请对首句中的“网”字进行赏析。

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(2)这首诗表现作者什么样的情绪？请进行简要分析。

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B

Volunteers, as an essential part of a successful world exposition, are a major channel for the public to participate in, serve and share the world exposition and a means to showcase the image of the host country and city. The following information is about the volunteer for the World Exposition 2010 Shanghai China．

I．Basic Requirements for Volunteers                         

●  Be willing to participate in voluntary services of Expo 2010;      

●  Age limit: Expo Site volunteers must be born before April 30,

1992 and Expo City Voluntary Service Station volunteers before

April 30, 1994;

●  Obey the laws and regulations of the PRC;

●  Be able to participate in training and relevant activities before the opening of Expo 2010;

●  Possess necessary knowledge and skills needed by the position;

●  Be in good health to meet the requirements of corresponding voluntary positions．

II．Further Information for Volunteers

●  Source

Residents of Chinese mainland, Hong Kong, Macau and Taiwan, as well as overseas Chinese, and foreigners can all apply to be the volunteers．

●  Signup methods

Applicants may log in onto the official websites for online signup．They may also consult or connect with the Expo Volunteer Stations．

●  Time

May 1 - December 31, 2009

Ⅲ．Volunteer Training

Volunteer training includes general training, special training and position training．General training is carried out through internet, while special training and position training are provided through classroom lectures and field practice．

IV．Volunteer Types

●  Expo Site volunteers refer to those offering voluntary services to visitors and the Organizer in the Expo Site, mainly including information, visitor flow management, reception, translation and interpretation, assistance for the disabled, and assistance in media service, event and conference organization and．volunteer management．

● Information booth volunteers are stationed in the Expo's information booths at key transportation centers, commercial outlets, tourist attractions, restaurants, hotels and cultural event places outside the Expo Site．They offer services including information, translation, interpretation and even first aid．

60．If you were born in April 1993, where can you be a volunteer?

A．In the Expo City．          B．In the host country．

C．In the Expo Site． D．In Chinese mainland

61．Which of the training will be done on the Internet?

A．Position training．             B．General training．

C．Classroom training．                 D．Special training．

62．Which of the following service is offered by information booth volunteers?

A．Visitor flow management．      B．Helping the disabled

C．Assistance in media service． D．Emergency First aid．

微灌技术是一种新型的节水灌溉工程技术，它比喷灌省水（）

A.15%～20%

B.20%～30%

C.30%～40%

D.40%～50%

（）是井巷掘进施工中的主要工序，其他工序都要围绕它进行有序安排。