1.Please describe the SAR of analgisics and anesthetics of benzoic acid esters. 2.What characteristics should be satisfied as ideal general inhalation anesthetics? 3.Think about the possible metabolism route and metabolites of procaine. 4.Please illuminate the structure modification of morphine at position 3,6,and 17,how to effect the activity of opioids analgesics1. Please describe the SAR of analgisics and anesthetics of benzoic acid esters. 2. What characteristics should be satisfied as ideal general inhalation anesthetics？ 3. Think about the possible metabolism route and metabolites of procaine. 4. Please illuminate the structure modification of morphine at position 3, 6, and 17, how to effect the activity of opioids analgesics