It was 1969 _____ the American astronauts succeeded in landing on the moon.
People have always been ______ about exactly how life on earth began.
As a child , Jack studied in a village school , _____ is named after his grandfather.
--- I cannot find Mr. Smith. Where did you meet him this morning? --- It was in the hotel ____ he stayed.
The workers ______ the glasses and marked on each box“ This Side Up”
We _______ on this project for four hours. Let’s have a rest.