Copper has been used since ancient times as a durable, corrosion resistant, and weatherproof architectural material. Roofs, flashings, rain gutters, downspouts, domes, spires, vaults, and doors have been made from copper for hundreds or thousands of years. Copper's architectural use has been expanded in modern times to include interior and exterior wall cladding, building expansion joints, radio frequency shielding, and antimicrobial indoor products, such as attractive handrails, bathroom fixtures, and counter tops. Some of copper's other important benefits as an architectural material include its low thermal movement, light weight, lightning protection, and its recyclability.
What is an important benefit to using copper as an architectural material?
low thermal movement

The languages have not undergone the deliberate highlighting of minor linguistic differences in the name of nationalism as has occurred in the Bosnian, Serbian and Croatian standards of Serbo-Croatian. However, most Slavic languages (including Czech) have been distanced in this way from Russian influences because of widespread public resentment against the former Soviet Union (which occupied Czechoslovakia in 1968). Czech and Slovak form a dialect continuum, with great similarity between neighboring Czech and Slovak dialects. (See "Dialects" below.)
Why have many Slavic languages sought to separate themselves from Russian influence?
widespread public resentment against the former Soviet Union

Early during the Taiping Rebellion, Qing forces suffered a series of disastrous defeats culminating in the loss of the regional capital city of Nanjing in 1853. Shortly thereafter, a Taiping expeditionary force penetrated as far north as the suburbs of Tianjin, the imperial heartlands. In desperation the Qing court ordered a Chinese official, Zeng Guofan, to organize regional and village militias into an emergency army called tuanlian. Zeng Guofan's strategy was to rely on local gentry to raise a new type of military organization from those provinces that the Taiping rebels directly threatened. This new force became known as the Xiang Army, named after the Hunan region where it was raised. The Xiang Army was a hybrid of local militia and a standing army. It was given professional training, but was paid for out of regional coffers and funds its commanders — mostly members of the Chinese gentry — could muster. The Xiang Army and its successor, the Huai Army, created by Zeng Guofan's colleague and mentee Li Hongzhang, were collectively called the "Yong Ying" (Brave Camp).
What was Zeng Guofan?
Xiang Army