The letter was shown to Lady Macbeth that Macbeth was entitled Thane of Cawdor and details of meeting the witches
I must complete is the adverb phrase
the world taxes or the stone
Proctor states that he hopes that by bringing the girls deceptions to light, it will free his wife, Elizabeth. Danforth and Cheever believe that Proctor wants to overthrow the court proceedings, and attempt to discredit him by using his poor attendance in the church.