What were you doing when I called you at 8 p.m. yesterday?—I the piano at that time.

My father was reading newspapers ____ my mother was cooking at this time yesterday evening.

It’s 12 April today. Have they found any useful information about the plane’s black box?—Flight MH370? Yes, but it’s difficult to decide where the black box really is.

I want to save money and then travel all over the world. [ ]

What do you mean _____ “bike”?[ ]