Answer:
1. They needed 2 days, although, the beaches were connected five days later.
Explanation:
This was a largest amphibious attack in the history of mankind. Around 156 000 troops stormed the beaches of Utah, Omaha, Juno, Gold and Sword. The attack started at dawn, on 6th of June, and was even delayed because of bad weather. Though the troops had many casualties at the end they managed to take over and connect these beaches.
2. U.S. General trick the Germans by leaking fake attack plans .
What Germans believed is that the attack will happen days later, more to the north, around the city of Calais. That is why some German officer were not even on the battlefield, but in Paris, expecting the invasion to come days later. They were tricked and because of that Germans were not fully prepared for this type of operation.
3. they needed time to gather resources
The Great Three could not agree on how to fight the Germans from the beginning. Stalin asked for help since the start, but the Anglo-American troops believed that they are not fully prepared for the fight on the other fronts, as they needed to gather resources to continue fighting in Northern Africa and Sicily.