1) The Berlin Conference in 1884-1885 divided Africa among European powers and set the stage for the colonization of the continent.

2) The first successful mass-produced personal computer, the IBM PC, was introduced in 1981 and played a significant role in popularizing the use of computers in homes and offices.

3) The development of the World Wide Web Consortium (W3C) and web standards has ensured interoperability and compatibility across different web browsers and devices.

4) The word "triangle" contains four vowels: I, A, E, and E.