Complex sentence: He explains that his people have discovered that time is more resilient than they had first believed but, because of the changes enacted by Ben and the Tourists, all time excursions have been suspended pending a full investigation.
Split into simpler sentences: He explains that his people have discovered that time is more resilient than they had first believed. However, because of the changes enacted by Ben and the Tourists, all time excursions have been suspended pending a full investigation.