Conversation so far:
what is BASIC?
programming language.
when did he develop BASIC?
After Gates read the January 1975 issue of Popular Electronics, which demonstrated the Altair 8800.
was he able to secure a job because of inventing BASIC?
Gates took a leave of absence from Harvard to work with Allen at MITS in Albuquerque in November 1975.

Question: did he further develop BASIC?
Self-contained rewrite: Did Bill Gates further develop BASIC?