Sam is doing his homework（对划线部分提问）doing his homework划线部分PS：如果doing his homework被划线提问,那么我就不知道Sam is doing his homework是现在进行时,那么我回答时到底用What is Sam doing?还是What is Sam do?
问题描述：
Sam is doing his homework（对划线部分提问）
doing his homework划线部分
PS：如果doing his homework被划线提问,那么我就不知道Sam is doing his homework是现在进行时,那么我回答时到底用What is Sam doing?还是What is Sam do?
答