The English people usually don't pronounce the Letter R unless its followed by a vowel as in "the doctor announced" and some other special cases ,so when they say "the car has broken down " it actually sounds like "the ca has broken down"but it would be hard to say "the ca is green for example" so they just add an r at the end of any word that ends this way even if it doesn't have an r at the end of itso "the idea is" will sound like "the idear is"and "the idea has" will remain the same