求翻译：这次事件是继第二次世界大战期间珍珠港事件后，历史上第二次对美国造成重大伤亡的袭击。这次事件是人类历史上截至2001年底为止最严重的恐怖袭击事件。是什么意思？

This event is following the Pearl Harbor during World War II, the second time in history caused major casualties of the attacks on the United States. The incident is the human history up to the end of 2001, the worst terrorist attacks.

This incident was the second Pearl Harbor during World War 2 after the incident, the first in the history of the United States 2 times cause significant injury or death. This is a history of humanity at the end of 2001 the most serious incident of terrorist attacks.

This event is after the Second World War period Pearl Harbor Incident, in the history second time causes the heavy casualty to US the attack.This event was in the human history up to 2001 year's end up to the most serious terror attack event.

This incident was during World War II after Pearl Harbor, the second time in the history of United States attacks causing heavy casualties. This is the history of mankind at the end of 2001, the most serious terrorist attacks.

正在翻译，请等待...