The building is so old that it should be at once . A. sold outB. broken down C. pulled do

问题补充：

The building is so old that it should be at once .

A. sold outB. broken down C. pulled down

答案：

解析：sell out“卖完”；break down“分解，出毛病”；pull down“摧毁，推倒”。根据句意“那栋大楼是如此的陈旧以至于应该立刻被拆除。”故选C。