Is that her pencil Their history teacher is Miss Yang

Are those her pencils?
Who is their history tearcher?
How old are you?

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1. Is she hair the subject and the predicate singular or plural
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8. She has short hair
9. She is from America and she has short hair
10. She has short hair! She has short hair _______ _______ _______ _______ .
11. Is that your pencil
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15. Is the plural number of mango plus s or es?
16. Is the complex number of logo plus s / es?
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19. On the plural form at the end of the English word (noun) f, Some English words (nouns) end with F, but in the plural form, we should not only change f into V and add es, but also remove the first (or last) letter of F. please list 3-5 such words and give explanations. Give points according to the answers! ╭╗ ╔╮ ╭╗ ╔╮╭╦═ ╗╮ ╔═╠═║║╔═╠═║║ ║ ║╝ ╔═╠═║╝╔═╠═║╝╚╠══╠╝ ╔═╠═╠╝╔═╠═╠╝ ║ ║║ ╔══╠╩╗╔══╠╩╗╰╠╝╔╠╯ ╚╝ ╝╚╯╚╝ ╝╚╯╚╯ ╯╰╝
20. Chocolate plural