In the late 1700s and the earlier 1800s, the development of the piano coincided with the growth of the middle class in Western Europe.

在18世纪晚期和19世纪早期，钢琴的发展恰好与西欧中产阶级的壮大是同步的。

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Engineering became a discipline in about the middle of the 1800s.

工程学在19世纪中期成为一门学科

耶鲁公开课 - 生物医学工程探索课程节选

The chapel was built in the middle of the 1800s for both non-conformist and conformist burials according to local historian David Wills.

BBC: The old chapel on Stoke Doyle Road