Ever since human beings ________ the Earth, they ________ use of various form of communication.

     A. have inhabited / have made                   B. inhabited / are making

     C. had inhabited / had made                      D. inhabit / make

In the 19th century, it ________ two or three months to cross North America by covered wagon. The trip ________ very rough and often dangerous.

I ________ the same car for more than ten years. I ________ about buying a new one.

- I called you last night after dinner, but you were not there. Where ________?

     - I ________ overtime at the fitness center.

They ________ good preparations before they ________ their final examination yesterday.

Those drivers ________ for three hours when a heavy storm suddenly ________

My best friend and I ________ each other for over fifteen years. We still ________ together once a week.

I ________ a mystery movie on TV when the electricity ________ out.