Pearl Harbor

Pearl Harbor is a military base on the Hawaiian island called Oahu.
On the 7th of December 1941 Japanese aereo airborn naval forces attacked the American base in the harbor.
While the attack was happening Japan was declaring war on the United States.
During the assault of 350 Japanese planes, four of the eight American battleships (dreadnoughts) were destroyed and the other four beached.
There were 96 American ships and 26 of them were destroyed or damaged.
There were approximately 2,600 slain from both sides.
Only the three aircraft-carriers missed being destroyed, in fact in the meantime they were having a square-bashing.
The attack was planned and headed by Admiral Isoroku Yamamoto. From then on and until the end of the 1941 the Pacific sea was dominated by the Japan Navy.
After this attack, on the 8th of December 1941, the United States declared war on Japan.

Red is errors Green is suggestions

Perl is a computer programming language!

Line 2 could be either a Jap... force or ... forces

I have resisted the temptation to correct your spelling of harbour! ;^)

'in fact in the meantime' is not the right phrase to use here. Neither (I think) is square bashing. That is soldiers marching around a square, which ships don't do!

Some options for that sentence:

Only the three aircraft-carriers missed being destroyed, due to the fact that at the time they were out of harbor on manouevres.

Only the three aircraft-carriers missed being destroyed, because at the time they were away doing exercises.