Your local firms used to ______ up quotations regularly.

Your local firms used to ______ up quotations regularly.
A、send
B、sending
C、be sent
D、being sent
【正确答案】：A
【题目解析】：句意：你方公司过去常常给我方寄报价单。used to do sth．表示“过去常常做某事”；be/get used to doing sth．表示“习惯于做某事”，故排除B，D项。句中主语与send之间为主动关系，故选A项。