Complex sentence: By 27 April, Berlin became completely cut off from the rest of Germany and secure radio communications with defending units had been lost; the command staff in the bunker were depending on telephone lines for passing instructions and orders and on public radio for news and information.
Split into simpler sentences: By 27 April, Berlin was completely cut off from the rest of Germany. Secure radio communications with defending units had been lost; the command staff in the bunker were depending on telephone lines for passing instructions and orders and on public radio for news and information.