如图所示，竖直放置的轻弹簧将物块1与2连接，物块1、2的质量分别为m和M．令物块

图为可测定比荷的某装置的简化示意图，在第一象限区域内有垂直于纸面向里的匀强磁场，磁感应强度大小B=2.0×10^-3T，在X轴上距坐标原点L=0.50m的P处为离子的入射口，在Y轴上安放接收器，现将一带正电荷的粒子以v=3.5×10⁴m/s的速率从P处射入磁场，若粒子在y轴上距坐标原点L=0.50m的M处被观测到，且运动轨迹半径恰好最小，设带电粒子的质量为m,电量为q, 不计其重力。则上述粒子的比荷（C/kg） 是

A．

B．4.9×

C．

D．

下列有关传染病和免疫的叙述，错误的是（　　）

A．传染病是由病原体引起的，具有传染性和流行性

B．传染病的流行必须具备三个基本环节

C．能引起人体产生抗体的物质叫抗原

D．由于人体具有三道防线，所以尽管有不良卫生和生活习惯的人也不会患传染病

2011 TEEN TRIP TO THE LELAND HIGH SNOW PLAY

For Teens Currently in 6th to 12th Grades

LELAND HIGH SNOW PLAY -- Class # 8389

Saturday, February 12, 2011

8:00 a.m. to 7:00 p.m.

Meet at THE UNDERGROUND (Veteran's Building -- 2203 Central Avenue)

Cost per person: $50 ($60 after January 22, 2011) Includes Lunch, Admission and Transportation

With a 4,000 sq. Ft. day-use lodge, the Leland High Snow Play has a huge supply of tubes to choose from, along with awesome tows (拖车) that will tow you up to the top of the hill! Our varied terrains (地形) have something for everyone, while the lodge provides a snack bar, video games, pool tables, five indoor rest rooms, a warm fire, and a sun deck with plenty of tables and chairs overlooking the play area outside. ADDITIONAL LIABILITY FORM REQUIRED FOR THIS TRIP.

Be sure to bring warm clothing and prepare for the cold, but dress in layers in case it warms up. Wear dry boots, socks, and sunscreen. If possible, bring a mobile phone in case of emergency, as well as money for snacks and a light dinner: or bring your own food and drinks.

Meet at The Underground (Veteran's Building -- 2203 Central Avenue) -- don't be late!

Do not bring electronic or fragile items during the trip. The ARPD is not responsible for your personal belongings or money. REFUNDS ARE ISSUED ONLY IF THE ARPD CANCELS THIS TRIP DUE TO WEATHER CONDITIONS.

Click here to download "2011 Leland High Snow Play" flyers and the registration form (PDF, 261KB)

Click here to download "Leland High Snow Play Liability Form" (PDF, 14KB)

1. You may register in person, or mail the completed form to Leland High Snow Play, Inc.

Send the liability form and payment to the ARPD Office, 2226 Santa Clara Avenue, Alameda, 94501.

2. Faxed registration and liability forms accepted with MasterCard/VISA, (510) 747--7566.

3. Online registrations available at www.arpdeplay.com. Make sure you bring your completed liability form on the trip.

小题1:The purpose of the text is to ________.

A．explain the details of a school activity

B．introduce a famous tour agency

C．urge teenagers to climb a snowy mountain

D．advertise a trip to the Leland High Snow Play小题2:People who want to take part in the activity need to ________.

A．pay for dinner themselves

B．climb the hill themselves

C．wear hats to protect themselves from the sun

D．pay for tows individually小题3:From the text we can infer that ________.

A．the weather at the hill is changeable

B．the activity is very dangerous

C．12-year-old children are not allowed on the trip

D．the trip will involve outdoor activities only.小题4:To save money people should ________.

A．climb the hills instead of taking tows

B．bring extra clothing

C．register for the activity before January 22

D．register on the Internet after January 22

小冬开展了一个大学生人际交往小组，他在小组中强调组员之间的互动，通过组织小组活动及组员之间的互动，发掘组员的自身潜能，增强他们社会交往与社会生活的信心、知识和能力。小冬在这个过程中使用小组工作的一个重要模式，符合这个模式的实施原则的有()。

A.使能者原则

B.积极参与原则

C.开放性的互动原则

D.平等性的互动原则

E.面对面的互动原则

九届全国人大常委会第十二次会议，通过了《关于取缔邪教组织、防范和惩治邪教活动的决定》。该决定通过的时间是（）。

A.1999年10月30日

B.1999年10月1日

C.2000年10月1日

D.2000年12月1日