某男，70岁，嚼肌发达，2年前全口义齿修复，最近来复诊，要求修理。检查：义齿着色严重，基托之间有1cm裂隙，并伴有牙齿折断，固位良好

临床上全口义齿上颌腭侧基托折裂的方向是()

A．从前向后

B．从后向前

C．裂隙由左向右

D．裂隙向四周呈放射状

E．以上都不是

I don't remember _____ the boy by himself. [ ]

A. why did she leave

B. why she left

C. why had she left

D. why she had left