1. Event = time+place+process+consequence+impact;

2. Person = time (country name)+position+action+evaluation;

3. Works = time+author+content+meaning;

4. Meeting = time+place+people+content+function;

5. Treaty = time+place+signatory+content+influence;

6. Reform = time+reformer+content+meaning;

7. Battle = time+both sides of the battle+process+consequences;

2. Add and subtract memory:

For example, after World War II, it can be recorded as:

After = four sudden attacks (sudden attacks on Poland, Denmark and Norway, the Soviet Union and Pearl Harbor)+six major battles (Moscow, Stalingrad, Kursk, the conquest of Berlin, the British air war and the naval battle of midway)+four important conferences (Cairo, Tehran, Yalta and Potsdam)+three landings (North Africa, Sicily and Normandy)+anti-fascist United front. This is all the historical events of the Second World War.