Thetrainleaves

來源：國語幫 2.45W

The train leaves____6：00 pm, so I have to be at the station ____5：40 pm at the latest? 　A. at； until B. for； after　C. at； by D. before； around

C。具體時間即點時間前常用介詞at, 表示“到……為止”用by。