Men (to be)____________interested in the stars ever since they first (to look) _________into the sky. In the past they (to think) _________that the sun (to move)_________round the earth and that you (to fall)_______________off the earth if you (to step) _________off at the end of it.

Men have been interested in the stars ever since they first looked into the sky. In the past they thought that the sun was moving round the earth and that you would fall off the earth if you stepped off at the end of it.