解释下列句子中加粗的字词。
①非梧桐不止:_________________________________
②非练实不食:_________________________________
③非醴泉不饮:_________________________________
④请循其本:___________________________________
⑤子之不知鱼之乐全矣:_________________________
⑥安知鱼之乐:_________________________________
⑦惠子相梁:___________________________________
⑧搜于国中三日三夜:___________________________