A
In an effort to inform our citizens of clearing the street snow，the city adopts a snow removal plan.
Routes used by City Emergency Services come first. Secondly，connected streets will be cleared，which allows citizens the greatest access to public roads. And thirdly，roads within neighborhoods will be cleared.
Snow removal and ice control will start when：
* Snow accumulates 4 inches or more.
* Weather conditions do not endanger the safety of the road crew.
* Snow falls during peak traffic periods of heavy use of main streets.
Snow and ice removal will be delayed or cancelled when：
* There is severely cold，significant wind and limited visibility.
* The snowfall occurs on the weekend or a holiday and is not considered a threat to public safety. In that case，snow and ice removal may take place on the next normal weekday.
*Snow and ice may be left on roadways if melting is obvious.
Your cooperation is requested during snow removal and these suggestions may apply：
* Limit travel during storms. Travel is possible once roads have been cleared or salted by the road crew.
* Avoid removing snow from your driveway into the road. Pile the snow in your yard.
* Park your vehicles in your driveways and off the road or walks.
* Keep public sidewalks next to your house clear of snow and ice.
* Be responsible for removing this snow which is thrown by the snow plough (犁) from your driveways. Hopefully，you can understand this inconvenience.
21．When will the snow have to be removed?
A．If it reaches a certain thickness. B．If the main streets are not busy.
C．If the snow and ice begin to melt. D．If extreme weather makes roads dangerous.
22．What should citizens do to cooperate in the snow removal?
A．Help to put the salt on the road. B．Pile the snow nearby to the road.
C．Throw the snow into the driveways. D．Clear the sidewalks close to their houses.
23．Which of the following is TRUE according to the text?
A．Clearance of emergency routes has a priority.
B．Snow and ice must be removed on the weekends.
C．Citizens play the most important role in snow removal.
D．The poster is to inform citizens of an oncoming heavy snow.
