Chronological structure:
"When Hall sensed that the Zimmermann telegram would tip the balance ... the British home secretary presented the telegram."
- The "when" clause shows that this was a chronological pattern of decision. When one thing was seen to be the case, the next course of action followed.
Cause-and-effect structure:
"News of the Zimmermann telegram was splashed across the front page of American newspapers. On April 6, 1917, the Congress of the United States declared war on Germany and its allies."
- The declaration of war is presented as a direct result of the news of the Zimmermann telegram hitting the papers. That's a cause-and-effect structure.