1. Not only . but also.引导的倒装 The activitynot only can enhance our English level , but it can also broaden our horizons.-(not only 放在句首，not only后用部分倒装，but also后不到装）-Not only can the activity enhance our English level, but it can also broaden our horizons.(活动意义)2. Only+副词/介词短语/状语从句作主语，句子用部分倒装Only recently did I understand what he did for me.Only in this way can we live in a more harmonious society.Only when he told me did Iknow the truth.3.The reason why+完整句子is that+完整句子
