What does the passage mainly discuss?
B. The participation of state governments in railroad, canal, and turnpike construction.
C. The roles of state and federal governments in the economy of the nineteenthcentury.
Chọn C
One of the first exercises in math class is ______ measure the radius of a circle.
_______ have settled, one of their first concerns has been to locate an adequate water supply.
Dick put ____ ball in ____ net in _____ second half but ____ goal was disallowed.
The computer has dramatically affected ______ photographic lenses are constructed.
Only after the atomic bomb ________ and development in the air travel _______, ______ science fiction really become popular.