They are swimming.改为否定句

They are swimming.改为否定句 They were swimming at that time.（改为否定句） They _____ swimming They are my boxes 改为否定句 they are smart.改为否定句 they are students改为否定句 They are pens(改为否定句） they are classmates改为否定句啊 They are apple改为否定句 they are making akite改为否定句 They are from Beijing改为否定句 they are my aunts.改为否定句 are they watching TV?改为否定句