Thank you, Angelika.
We've learnt these phrases at our vocational college that prepares for the exam for a foreign language teacher.
We had to learn all these phrases by heart. No one has ever advised us that there might be some mistakes in our book (a German one with phrases in English-German) except one teacher, but he doesn't teach this subject (business letter writing), so his influence is quite small. Once he tried to intervene and informed the other teachers, but there are convinced that it's easier to teach and learn with the book, especially for themselves.
Well, my exam is going to take place in June and I'm quite worried because of all these mistakes.
Sorry for my detailled answer. It didn't mean to digress that far. Besides I didn't want to give false information to Patou.
Thank you so much.