不是的。sheep是可数名词，只是它的单数和复数形式是一样的，请看下面的句子： The man looks after about eighty sheep. 这人放牧八十来只羊。 He is a black sheep in the family. 他是他家的败家子。 He had to take with him a sheep, a wolf and a basket of vegetables. 他必须带上一只羊，一只狼和一篮子菜。 people也不一定就不可数，当它作为人；人们; 亲戚；家族; 某地方的人或人民；公民；平民解释时，为集体名词，不可数，如The streets were crowded with people. 大街上挤满了人。The men who govern the country are chosen by the people. 治理国家的人是由人民选择的。 当它作为民族解释时，是可数名词，如The Chinese people are a brave and hard-working people. 中华民族是一个勇敢勤劳的民族。