500
                            List two pieces of evidence to support Chomsky's theory.
                                  Children learning to speak never make grammatical errors such as getting their subjects, verbs and objects in the wrong order.
       If an adult deliberately said a grammatically incorrect sentence, the child would notice.
       Children often say things that are ungrammatical such as ‘mama ball’, which they cannot have learnt passively.
       Mistakes such as ‘I drawed’ instead of ‘I drew’ show they are not learning through imitation alone.
       Chomsky used the sentence ‘colourless green ideas sleep furiously’, which is grammatical although it doesn't make sense, to prove his theory: he said it shows that sentences can be grammatical without having any meaning, that we can tell the difference between a grammatical and an ungrammatical sentence without ever having heard the sentence before, and that we can produce and understand brand new sentences that no one has ever said before.