It's not only correct but also proper to hyphenate the underlined words because they’re used as descriptive words (adjectives), isn't it?
grade-school pupils
high-school students
high-school curriculum
English-language lessons
English-language teachers
English-language learners
Rommel not only correct but also proper What's the difference?
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Rommel not only correct but also proper
What's the difference?
RommelIt'snot onlycorrect /but alsoproper to hyphenate the underlined words..., isn't it?
I'm not sure about hyphenated high-school that functions as an adjective. Better ask others.