I often have conversations with John over telephone, while keep in touch with Tom by letter.
A. 不填;;the
B. 不填;a
C. the;不填
D. the; a
网友回答
A. 不填;;the
B. 不填;a
(答案→)C. the;不填
D. the; a
解析：本题考查冠词的用法。前一个空over the telephone表示“通过电话”；by letter表示“通过写信”，by表示方式后直接接一个名词。