Question

E-shopping, when properly _____ ,can save us a lot of time and energy. A．done B．doing C．to

E-shopping, when properly _____ ,can save us a lot of time and energy. A．done B．doing C．to do D．is done

Answer 1

A

考查非谓语动词。逻辑主语E-shopping与do之间的关系为被动关系，故用过去分词，相当于when it is done properly，选A。