Are there any events that compare to 9/11

The  Bombing  Of   Pearl  Harbor might somewhat compare because of the amount of deaths (2,403) which is about 500 off

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).

“way of writing” should be replaced with “writing style"

“idea” should be replaced with “purpose.”

maybe   “people from a long time ago” should be replaced with “elizabethans.”