Answer:
In 1861, many did not believe the Civil War would last long; however, the fighting lasted four years.
Step-by-step explanation:
The Civil war was the deadliest war in the United States of America, the president at the time Abraham Lincoln wanted to abolish slavery and the fight between the Union and The Confederate States became brutal, this was a very long war were many died from little young to elderly fought. In this line, the word "however" is an expression of contrast in the ideas, which makes "the fight lasted four years" the best answer from being opposite to the first sentence that says people did not believe it would last long