she has aheadache.为什么用has,不是用have.而no,she doesn‘t have an earache用have是不是has用于肯定have用于否定和疑问

问题描述:

she has aheadache.为什么用has,不是用have.而no,she doesn‘t have an earache用have是不是has用于肯定
have用于否定和疑问

主语是第三人称单数:have(有)用has; 否定句用doesn't+动词原形
have是动词原形,根据人称、时态的不同,其变化形式为have,has, had

she为三人称的单数,用has,像I,you,they就用have,she/he/it就用has,短语don't do sth

当时态是现在时态,主语又是第三人称单数的肯定句时用has.后面的否定句中,因为doesn't这个词已经体现了时态和人称的单复数,所以要用原型have.