Excuse me, sir. Could you tell me _______?

A. where can I get a post card

B. where I can get a post card

C. that I could get a post card

在安装分段绝缘器时，在承力索断线处两侧适当位置各打紧一个楔形紧线器，并在其前面（即楔形紧线器受拉侧）承力索上安装钢线卡子或吊线线夹，以防紧线时楔形紧线器滑动。