Text structure is how you organize your information. For example, you may want to organize it in a cause/effect scenario, or using chronological order. For example, a text structure can take on the form of such:
First, Japan surprised attack Pearl Harbor even when they were trying to hold peace conferences with the USA as a promise that they would hold the US's neutrality. This leads to President Roosevelt's famous "Day of Infamy" speech, which led to the US declaring war on the Axis Powers, and the internment of Americans with Japanese Ancestry (Nisei and Issei). Finally, the Issei's had to endure harsh treatments in the camps, and were finally let out of the camps following the Japanese surrender.
While this does not give the complete picture, it gives a feeling of a chronological order (in which after the attack of Pearl Harbor, it led to the Infamy speech, which led to the internment of Japanese Americans). It also gives a cause and effect (because of the attack, there is consequence for the Japanese Americans). This is just one of the structures you can use, but of course there are many more examples you can give.
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