When Jim’s mother came in he his homework.Ais doing B．has done C．was doing

问题补充：

When Jim’s mother came in, he his homework.

A．is doing B．has done C．was doing

答案：

解析：句意：当吉姆的母亲进来时，他正在做他的作业。结合语境可知本句描述是的是过去某时正在进行的动作，故用过去进行时态。选Ｃ。