题目

Not until all the fish died in the river, ________ how serious the pollution was. A . did the villagers realize B . the villagers realized C . the villagers did realize D . didn't the villagers realize 答案：A6．下列四组疾病中，因缺乏激素而引起的一组是（　　）A．呆小症和地方甲状腺肿B．夜盲症和佝偻病C．侏儒症和糖尿病D．白化病和色盲症