Question: When did the us enter the second world war in europe?

Disambiguated questions and answers:
context: The military history of the United States in World War II covers the war against the Axis powers, starting with the 7 December 1941 attack on Pearl Harbor. During the first two years of World War II, the United States had maintained formal neutrality as made official in the Quarantine Speech delivered by U.S. President Franklin D. Roosevelt in 1937, while supplying Britain, the Soviet Union, and China with war material through the Lend-Lease Act which was signed into law on 11 March 1941, as well as deploying the U.S. military to replace the British invasion forces in Iceland. Following the "Greer incident" Roosevelt publicly confirmed the "shoot on sight" order on 11 September 1941, effectively declaring naval war on Germany and Italy in the Battle of the Atlantic. In the Pacific Theater, there was unofficial early U.S. combat activity such as the Flying Tigers.
question: When did the US start funding/supplying the second World War in Europe?
short_answers: 11 March 1941
wikipage: Military history of the United States during World War II
context: No context provided
question: With the signing of what legislation did the US start funding/supplying the second World War in Europe?
short_answers: Lend-Lease Act
context: The military history of the United States in World War II covers the war against the Axis powers, starting with the 7 December 1941 attack on Pearl Harbor. During the first two years of World War II, the United States had maintained formal neutrality as made official in the Quarantine Speech delivered by U.S. President Franklin D. Roosevelt in 1937, while supplying Britain, the Soviet Union, and China with war material through the Lend-Lease Act which was signed into law on 11 March 1941, as well as deploying the U.S. military to replace the British invasion forces in Iceland. Following the "Greer incident" Roosevelt publicly confirmed the "shoot on sight" order on 11 September 1941, effectively declaring naval war on Germany and Italy in the Battle of the Atlantic. In the Pacific Theater, there was unofficial early U.S. combat activity such as the Flying Tigers.
question: When did Roosevelt publicly confirm the "shoot on sight" order, effectively entering the US in the second world war in Europe?
short_answers: 11 September 1941
wikipage: Military history of the United States during World War II
context: Following the attack on Pearl Harbor, President Roosevelt officially pronounced 7 December 1941, as "a date which will live in infamy" and asked for a declaration of war on Japan before a joint session of Congress on 8 December 1941. The motion passed with only one vote against it, in both chambers. Just three days later, on 11 December 1941 Adolf Hitler declared war on the United States, and had already remarked on the evening of the date of the Japanese attack that "We can't lose the war at all. We now have an ally which has never been conquered in 3,000 years".
question: When did the US officially enter the second world war in europe?
short_answers: 7 December 1941
wikipage: Military history of the United States during World War II
context: Following the attack on Pearl Harbor, President Roosevelt officially pronounced 7 December 1941, as "a date which will live in infamy" and asked for a declaration of war on Japan before a joint session of Congress on 8 December 1941. The motion passed with only one vote against it, in both chambers. Just three days later, on 11 December 1941 Adolf Hitler declared war on the United States, and had already remarked on the evening of the date of the Japanese attack that "We can't lose the war at all. We now have an ally which has never been conquered in 3,000 years".
question: Upon what event did the US officially enter the second world war in europe?
short_answers: attack on Pearl Harbor
wikipage: Military history of the United States during World War II

Long-form answers:
knowledge: content: Franklin Delano Roosevelt (/ˈroʊzəvəlt/,[1] /-vɛlt/[2] ROH-zə-velt; January 30, 1882 – April 12, 1945), often referred to by his initials FDR, was an American politician who served as the 32nd president of the United States from 1933 until his death in 1945.
wikipage: Franklin D. Roosevelt
long_answer: Prior to the United States entering world war II, U.S. President Franklin D. Roosevelt signed the Lend-Lease Act on 11 March 1941 to ensure the supply of war materials to Britain, the Soviet Union, and China. On 7 December 1941, following the attack on Pearl Harbor, the United States officially joined the second world war. A few days later (on 11 September 1941), President Roosevelt publicly confirmed the "shoot on sight" order, effectively entering the war. 
knowledge: content: By all accounts, a German submarine (later identified as U-652) fired upon the Greer, but made no contact.
wikipage: USS Greer (DD-145) The Greer incident, September 1941
long_answer: The US officially entered the Second World War in Europe on 7 December 1941 after the attack on Pearl Harbor. President Roosevelt signed the Lend-Lease Act into law on 11 March 1941, which supplied Britain, the Soviet Union, and China with war material and deployed the US military. Following the Greer Incident, which was when a German submarine fired upon the Greer, Roosevelt publicly confirmed the "shoot on sight" order on 11 September 1941, effectively entering the US in the Second World War in Europe.