…,but the only people who do succed are those who work hard为什么有only修饰了people而不用that（不是只能用that吗）

…,but the only people who do succed are those who work hard为什么有only修饰了people而不用that（不是只能用that吗）
…,but the only people who do succed are those who work hard为什么有only修饰了people而不用that（不是只能用that吗）

…,but the only people who do succed are those who work hard为什么有only修饰了people而不用that（不是只能用that吗）
那是指物时相对which 来说的.指人时,这里that,who 都可以,因为做主语