英语怎么问对方体重怎么说

To ask someone their weight in Engpsh, you can say:

"How much do you weigh?"
"What is your weight?"

It is generally considered impopte to ask someone about their weight, unless you have a specific reason to do so (for example, if you are a healthcare provider or if you are asking in the context of a weight loss program). If you do need to ask about someone's weight, it is best to be sensitive and respectful in your language.