英语 (2 19:15:12)He began to do his homework when his mother came back.(同义句)

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英语 (2 19:15:12)
He began to do his homework when his mother came back.(同义句)

He didn't begin to do his homework untill his mother came back.
He began to do his homework as soon as his mother came back .

He began to do his homework as soon as his mother came back .

He didn't begin to do his homework untill his mother came back.