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Hi

Would you please tell me what does the phrase "rave over" mean in this context?

Bright boys rave over young girls.
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To rave over X is to bestow exaggerated praise on X.

The praise would not necessarily be delivered directly to the "objects of praise."
The "bright boys" might simply be "raving" amongst themselves over/about the charms of the "young girls" in question.

In the same manner, they could "rave over" the features of a new automobile design.
Comments  
Students: Are you brave enough to let our tutors analyse your pronunciation?
They are very excited and/or talking enthusiastically (almost like a madness) about girls.
Thank you, Avangi, Lakswadeep.