How can you tell if someone read your email?

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Tags

1. #would
2. #receipts
3. #email
4. #communicate
5. #receipt
6. #sparingly
7. #whether
8. #check
9. #there
10. #confirm
11. #urgent
12. #method
13. #important
14. #emails
15. #person
16. #message
17. #reliable
18. #extra