套筒锁紧装置需要将套筒固定在某一位置时，可顺时针转动手柄，通过圆锥销带动拉紧螺杆（）

顺气和中汤2功效与作用

Washington D. C. is a great city to live in and visit – partly because D. C.’s public transportation can get you almost anywhere in the city, D. C.’s subway, the Metro, is great for getting you to the main tourist sites, but the bus is also a great resource and is cheaper. Learn how to conquer the D.C. bus system in a few quick steps will help you to have fun in this city.

* Things You’ll Need, cash or a D. C. Smart Trip card, a transfer (转乘卡) and a map of Washington, D. C.

* To choose a bus line to take from home or your hotel, look at the buses that arrive at the closest Metro stations.

Many bus routes start at a Metro subway terminal and make their way across the greater D.C. area.

*Learn to identify bus stops. They are usually located at the intersections(交叉) of streets. Look for a tall sign with a tall sign with the words of “Metro Bus” that is dark blue at the top, white in the middle and red at the bottom. Once you’ve found one of these signs, check the red section at the bottom of the sign. In it, you should see several number or letter combinations written in white. Those are the bus lines that service that stop.

*Be careful of the direction buses are heading for. All buses have an electronic screen on the front, side and back of the bus that let you know which way they are headed and what line the bus is. The signs will list the last stop on the bus route. Know where your bus terminates on each end so you can get on the bus heading in the direction you want to go.

*To board the bus, you'll obviously need some sort of payment. The bus will only accept cash or a SmarTrip card. SmarTrip cards are purchasable at several Metro stations or at Metro headquarters(总部) and cost $5. You can also buy the card online at www.wmata.com.

*If you do order it online, purchase it in advance as it will take time for it to ship. Riding the bus costs $1.35 if you pay in cash and $1.25 if you pay with your SmarTrip card.

*If you pay in cash, ask for a transfer slip. This will allow you to board the bus within a two-hour time period without having to pay again. These machines are located by the escalators that take you to the waiting platforms.

小题1:To enjoy a wonderful tour in Washington D. C., you won’t need        .

A．a D. C, Smart Trip card                       B．a transfer

C．a map of Washington D. C                    D．a tall sign

小题2:According to the passage, you can identify bus stops by           .

A．looking at the buses that arrive at the closest Metro station from your hotel

B．checking the red section at the bottom of the sign with a “metro bus” logo

C．checking electronic screens on the front, side and back of the bus

D．checking the machines located by the escalators taking you to the platforms小题3:The underlined word “terminates” probably means        .

A．stops

B．decides

C．starts

D．passes小题4:Where can you get a Smart Trip card?

A．At a platform.

B．At a post office.

C．At www. wmata. com

D．At a bus station.

高档相机的价格需求弹性为2，当（）时相机需求量下降50%.

A、价格增加20%

B、价格降低20%

C、价格增加25%

D、价格降低25%

什么是颈袢？甲状腺手术如何避免伤此神经？