verb
1
BAD : When I discuss with them, I cannot say the things that I want to say, because of my English.
GOOD : When I talk to them, I cannot say the things that I want to say, because of my English.
BAD : Some people were discussing; some listening to the radio.
GOOD : Some people were talking; some listening to the radio.
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Discuss is a transitive verb and needs an object: 'I'd like to discuss my homework with you.' 'The two sides will discuss further arms reductions.'
2
BAD : They'd like to discuss about what to do next.
GOOD : They'd like to discuss what to do next.
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discuss sth (WITHOUT about/on ): 'He simply refuses to discuss the matter.' 'There is nothing to discuss.'
Compare talk about, a discussion about/on : 'They want to talk about what to do next.' 'They want a discussion about/on what to do next.'