The us began fighting in afghanistan in 2001

The statement is true. The US began fighting in Afghanistan in 2001, after the terrorist attacks of September 11th.

Explanation:

After 9/11, the clues of those responsible for the terrorist attacks in New York led to the terrorist organization Al Qaeda, headed by Osama Bin Laden. In 2001 Bin Laden was a refugee in Afghanistan, where there was a radical Islamist political regime by the Taliban. The Taliban came to power after the withdrawal of the invading army from the USSR in the late 1980s. The United States needed a strong military response to show the world its capacity to react to terrorist attacks on its territory.

In this previous context, the US initiated its actions against Afghanistan in October 2001. The Taliban regime refused to deliver Osama Bin Laden to the US, which led them to prepare a war to seize him even invading the country and overthrowing the Taliban regime.  

The military actions were quick and the US managed to overthrow the Taliban political regime and take the cities of Kabul and Kandahar in a month. In November 2001, the US considered that it had won the war. But his real objective, to capture Osama Bin Laden, had failed. Bin Laden and part of the Al Qaeda leadership in Afghanistan first fled to the mountains on the border with Pakistan (which are difficult to access militarily) and later camouflaged themselves within the population of Pakistan. Despite the political fall of the Taliban within the government of Afghanistan, they continued to dominate some territories and did not stop fighting against US military troops.