As the lesson explains an EXCEPTION that -s needs to be added in Tu form of -ER verbs with Adverbial Pronouns. Does that rule also apply in negation?
- Manges-en trois! [Eat 3 of them] --> N'en manges pas trois! [Don't eat 3 of them!] ??
- Achètes-en! [Buy some!] --> N'en achètes pas! [Don't buy any!] ??
- Vas-y! [Go there!] --> N’y vas pas! [Don't go there!] ??
- Manges-y! [Eat there!] --> N'y manges pas! [Don't eat there!] ??
