What things were invented in 1900?
There were many things invented in the 1900's. In 1903, the first airplane was invented by the Wright brothers. In 1905, plastic was invented.
One of the things that was invented was grammar. In place of singular verbs, the English language began to develop plural conjugations. In ye olde englishe, "they" and "that" were synonymous, but in 1784 they became separate words. For example, the sentence "What was the things they were invented in 1750 and 1900?" would become "What were the things that were invented in 1750 and 1900?".