确定不整合的时代一般是以不整合面以下最新地层时代为其（）；以不整合面以上最老地层时代为其（）。
参考答案：下限；上限
根据句意和汉语注释，在答卷标有题号的横线上，写出单词的正确形式。
小题1:He seldom __________ (回复) to the e-mails his friends send him.
小题2:Our English teacher has offered us some useful __________ (建议). I think they will help us a lot in our English study.
小题3:I came here __________ (专门) to invite you to my party.
小题4:Listening to music can make you forget your __________ (悲伤).
三相异步电动机调速
