【题目】There was a time _______, if a lady got onto a crowded bus or train, a gentleman would immediately stand up and offer her his seat.
A.whileB.asC.whenD.unless
在线课程【答案】C
【解析】
考查关系副词。句意：曾经有一段时间，如果女士上了拥挤的公共汽车或火车，男士会立即站起来给她让座。表示“曾经有一段时间”是there was a time when，先行词是time，在定语从句中作时间状语，用when引导定语从句。故选C。