英语完形填空：why do people like yellow pencils?

英语完形填空：why do people like yellow pencils?
Everybody uses one.There is one on my desk now.It is 1 .Is there one on your desk,too?2 am I talking about?Can you 3 what it is?It is a pencil.
4 pencils are about 18 centimeters long.One pencil can 5 a line thirty-five miles long,or write 45,000 6 One pencil may be sharpened (削尖) several times 7 it is too short to 8 ,yet we can buy one for the price of an orange!I think that pencils are very 9 .
　　Pencils are made in many different 10 ,but most people like yellow ones.There are more yellow pencils than any other color.No one knows why people like yellow pencils 11 they do.Someone once made a lot of pencils.Half were yellow and half were green.A man bought them and 12 them for a long time.Then he went to the market with them and said,“The green pencils,I’m sorry to say,are 13 good.They break easily.They are hard to be sharpened.They don’t write well.I don’t 14 any more green pencils.I want yellow ones in the future,please.”
　　But the pencils were 15 .The only difference was the color!
　　1.A.useful B.yellow C.a book D.a ruler
　　2.A.What B.Do you know what C.Who D.Do you know who
　　3.A.find B.remember C.know D.guess
　　4.A.Most B.Few C.Good D.Only a few
　　5.A.form B.cut C.write D.draw
　　6.A.stories B.words C.sentences D.books
　　7.A.when B.which C.before D.after
　　8.A.write B.sharpen C.draw D.use
　　9.A.common B.useful C.cheap D.expensive
　　10.A.countries B.colours C.sizes D.types
　　11.A.and B.but C.or D.that
　　12.A.has used B.used C.wrote with D.drew with
　　13.A.quite B.not only C.also D.not
　　14.A.need B.want C.sell D.make
　　15.A.the same B.different C.yellow D.useful