Why were the japanese able to advance in the pacific in 1942

In 1940, Japan entered into an alliance with Germany and Italy. This gave them an excuse to try and conquer the colonies of Europe situated in the Pacific. However, U. S. A issued an oil embargo towards the country. This led to December 1941, when Japan had attacked Pearl Harbor. Pearl Harbor was America's naval base and the loss of it crippled the country. America raged war. However, time was needed to recover. By 1942, Japan was left to conquer the countries in the Pacific left unguarded by Europe and America.