they are boys that can sing 可以.
that后和boys保持一致,除了加了the only one之类的限定是例外.they are boys there can sing 是对的吗？就是想问that的单复数形式和它代指的名词保持一致吗？they are boys there can sing好像语法上有问题。这句话什么意思？其实就是瞎想的，有点莫名其妙。。。哈