Was it in 1969 ________ the American astronaut succeeded ________ landing on the moon?
All his money had been ______,so he had to make a living by begging.
_________ the project as planned, we’ll have to work two more hours a day.
I feel greatly honored ____ into their society.
In his book,he explains both ______ it means to be a scientist and ______ science works.
The great scientist became world-known in the early 1970s,______ he and another scientist made new discoveries about black holes.