Each school day,yellow school buses take millions of American kids to and from school.
According to the law,school buses must be painted "school bus（1）______".You may not find it in a box of crayons.The colour is neither pure（纯的）yellow（2）______pure orange.Instead,it is a mix of the two,similar（3）______to the flesh（果肉）of a mango.
Before such a law was passed,school buses had been painted pure yellow,close to the colour of a（4）______.In 1939,Dr.Frank W.Cyr had a meeting to（5）______rules for US school buses.
This（6）______a standard colour for all school buses in the whole country.Since then,Dr.Cyr has been know（7）______the "Father of the Yellow School Bus".
The school bus yellow colour is not just for（8）______.It is also a matter of safety.Many people（9）______that red is the most noticeable（明显的）colour.Both stop signs and stop lights are red.In fact,research shows that yellow gets our attention(10)______than any other colour.Even if we are looking straight ahead,we can also see a yellow object（物体）that is going past(11)______.Besides that,unlike red,yellow is also more easily noticed in a(12)______environment.School buses usually(13)______children to school in early morning.The black lettering on that yellow background is the easiest colour combination（组合）to be(14)______in darkness.This is another main reason(15)______school bus yellow was chosen.