Some ducks are swimming in the pond对some ducks进行划线部分提问

问题描述:

Some ducks are swimming in the pond对some ducks进行划线部分提问

What is swimming in the pond?
单独用what/who提问做句子主语时,谓语动词只用单数.
再如:They are on duty today.
如果对they划线提问,答案是:Who is on duty today?Jone is swimming in the pond是对Jone划线提问吧?答案是:Who is swimming in the pond?