外贸函电题
1.We have received your letter of 15 Oct.in which you advise glad to know that you are interest in interested in our electric.
此处in which
2.We have recevied yor letter of Sep.12,from which we are glad to know that you are interested in our electric heaters.
此处的from which
3.We shall be pleased to send you the necessary information on our machine tools.
此处on何解?为何不可用 in?