蒸汽船在19世纪改变了沿河城镇的贸易方式。

In the 19th century, ___steamboats transformed trade along river towns.

蒸汽船在19世纪代表了工业革命对海上交通的巨大影响。

___Steamboats symbolized the tremendous impact of the Industrial Revolution on maritime transportation in the 19th century.