Complex sentence: He worked for a time at the U.S. Embassy in Sana'a in the mid- 1970's and came to the U.S. on a tourist visa on July 23,2001.
Split into simpler sentences: He worked for a time at the U.S. Embassy in Sana'a in the mid- 1970's. He came to the U.S. on a tourist visa on July 23,2001.