Before the first non－stop flight made in 1949

Before the first nonstop flight made in 1949, it

The writer implies in the first paragraph thatA．Louise Johannes was known before the 1940s

When were the chemicals first used in America？A．Before the American Revolution.B．Over thir

— You won the first prize in the Physics competition.— _________. I made several terrible mistakes.A

Edison failed _____ times before he succeeded in producing the first electric lamp .

In the first test each subject sat before a computer screen and pressed a key as soon as