单项选择题
A.was inventing B.invented C.had invented D.has invented
It is（）to interrupt the others while they are talking.A...
单项选择题It is（）to interrupt the others while they are talking.
A.rough B.rude C.polite D.troublesome
It was well known that Thomas Edison（）the electric lamp...
单项选择题It was well known that Thomas Edison（）the electric lamp.
A.invented B.discovered C.found D.developed
It was in（）the American astronauts succeeded in landing...
单项选择题It was in（）the American astronauts succeeded in landing on the moon.
A.when B.the moment C.which D.that
