Gao Shan’s sister likes playing table tennis （改为否定句） Gao Shan’s sister like playing tabled

Gao Shan’s sister likes playing table tennis （改为否定句） Gao Shan’s sister like playing tabled
为什么likes变成了like
变成 Gao Shan’s sister doesn't likes playing table tennis
其中的likes为啥变成like