填空题

A—acceptance letters
B—adjustment letters
C—application letters
D—collection letters
E—complaint letters
F—credit letters
G—inquiry letters
H—memorandums
I—order letters
J—reference letters
K—sales letters
L—news releases
M—annual reports
N—feasibility reports
O—investigative reports
P—progress reports
Q—trouble reports
R—trip reports ______投诉函 ______咨询信/询价函