Where in this sentence is there a grammatical error?

"by reading history we come to understand that civil wars have occurred in many countries including england, spain, and russia."

Fill in the blanks : -1)she " you are a murderer! ".2)" come back, simon", he and in tears.

Me i’m in need of answerering this

Read the excerpt from “strychnine in the soup,” in which mr. mulliner explains the ending of a mystery novel to a bar patron who is anxious to know the conclusion of the story. “the plumber forgot his snake and had to go back for it,” explained mr. mulliner. ‘‘i trust that this revelation will prove sedative.” “i feel a new man,” said the draught stout. “i’d have lain awake worrying about that murder all night.” explain how a student who did not know the meaning of sedative could infer its definition?