Hornby, A.S..
Teaching of Structural Words and Sentence patterns / - Fourth Impression 19 / - London W.1 : The English Language Book Society. - p.402 :
P,6:2(T:3) / K4;2
Teaching of Structural Words and Sentence patterns / - Fourth Impression 19 / - London W.1 : The English Language Book Society. - p.402 :
P,6:2(T:3) / K4;2