BECOME, BECOME OF
You use become to talk about changes and developments. If you become ill, you start to be ill after being healthy. If something becomes necessary, it is necessary now but was not necessary before.
1. When that happens, people become jealous.
2. When Uncle Nick was told about this, he became very quiet.
3. In less than a year Long Beach became the most crime-free town of its size in the United States.
If you ask what has become of somebody or something, you want to know what has happened to them.
4. He was a most diligent little man. The librarian wondered whatever had become of him.
5. What then becomes of the country’s concept of national security?