1. three: responsable ➝ responsible, grammer ➝ grammar, mispellings ➝ misspellings; 2. Joneses; 3. led, drunk; 4. me; 5. 3-year-old; 6. lay; 7. They are both correct! People will see the word “one” and automatically think the verb has to be singular (“is”) in both sentences. But in the second sentence, it’s not the singular number “one”; it’s “one percent.” If there were 400 students, that would be four chronically late students. The better choice there is “are.” 8. Plenty of people still put two spaces because they were taught to do that when people still typed on typewriters, but the convention in books, magazines and newspapers is one. Don’t let your typing habits date you.