滤毒罐外表凡有白道的，均置有滤烟层，还能防（）。A、毒烟 B、毒雾 C、有毒固体 D

Experience the newly opened Grand Canyon(大峡谷)West Skywalk in Colorado.Departing from Grand Canyon’s South Rim by Airplane to Grand Canyon’s West Rim,you will land and take a ground tour to the Skywalk!Walk on air for 70 feet over the edge of Grand Canyon West.
This Skywalk has been open since March 28,2007.Daily visitorship to the Skywalk has been over 4000 people.Please be patient to enjoy your moment on the Skywalk.
After you have experienced the one and only Grand Canyon Skywalk Glass Bridge,you will return to the Grand Canyon West Airport and take your Airplane for a flight back to the South Rim of the Canyon.This is a tour never to be forgotten as you will have walked on air over the Grand Canyon.
Tour Itinerary(行程)

Tour Duration	5.7 Hour	The Ground Canyon Adventure Skywalk
Flight from Grand Canyon South Rim to Grand Canyon West	1 Hour	Experience a bird’s-eye view of the Grand Canyon as you make your way to Grand Canyon West.
Light Lunch at Guano Point at Grand Canyon West	2 Hours	You will be taken by bus to Guano Point with breathtaking views of the western part of the Grand Canyon where the Colorado River makes its way into Lake Mead.Every table for lunch has a view.
Walk on the World Famous Skywalk	1.5 Hour s	Finally you will board your bus to Eagle Point,home of the Grand Canyon Skywalk.Now it is time for you to walk on air for 70 feet over the Grand Canyon.
Fight Back to Grand Canyon South Rim	1.2 Hours	After time on the Skywalk,you will return to the Grand Canyon West Airport and return to Grand Canyon South Rim in time for dinner and sunset.

小题1:This advertisement is for_______.

A．Grand Canyon West	B．Grand Canyon South
C．Grand Canyon	D．the Skywalk

小题2:The package fee does NOT cover the cost of_______.

小题3:The Grand Canyon Skywalk Bridge is made of glass because_______.

A．it looks stronger	B．it is cheaper to build
C．it looks more beautiful	D．it gives you a better view

小题4:According to the Tour Itinerary,the route is_______.
A.South Rim→Guano Point→West Airport→Eagle Point→West Airport→South Rim
B.South Rim→West Airport→Guano Point→Eagle Point→West Airport→South Rim
C.South Rim→West Airport→Eagle Point→Guano Point→West Airport→South Rim
South Rim→West Airport→Eagle Point→West Airport→Guano Point→South Rim