So between 1510 and 1514 Copernicus worked on it, gradually _____ his theory until he felt it was complete. [ ]

en are taught to respecteveryone, race,sex or age.

Lao She’s Teahouse ________ the changes in Chinese society over fifty years．

I don’t like ______ as you read.

How do you find the new job? — It’s hard to find _____ work so that I hardly care what it is _____ I can make a living. [ ]