I got the position with flying colors because the boss had only gotan elementary education, h in English. He was even unable to read the 26 English letters, and of the alphabet so both of us were satisfied with each other.

すごい！

I promised the boss I willthat I would master the specified and necessary vocabulary in a very short time.

This happened in the past so we used the past tense of "will" which is "would."

When foreign freighters or cargo ships arrived at Shenzhen port ( there are three ports there), my boss and I would get on the ship and ask for some business, t. The deals were all up to the captain.

They called us as ship chandlers.

In most cases, they would reject us because their company had signed a long-term agreement with somea big ship chandler in Guangzhou, t. They usually faxed all list of all their required products to Guangzhou several days ago when they prepared tobefore they entered the harbor.

"Some" is plural. I wasn't sure what you were trying to say here so here's another correction:

"In most cases, they would reject us because their company had signed a long-term agreement with some big ship chandlers in Guangzhou."

We only supplyied something that they had forgotten to list on the fax, which was also a big profit for us, however.

We musthad to visit the port every day to look for business and generally got a deal only about once a week, yet it was enough for us.

I remember the first time when I visited a captain from Israel,. I couldn't understand the meanings of "cement" and "coke", h." He didn't laugh at me and explainbut described them thoroughly to me.

At the same time, my boss looked at us radiantly with a smile, h. He was contented to watching how hard I was trying to work, h. He didn't know a word aboutof what we were discussing.

あー、優しい上司でしたね。

I sincerely want to showexpress my thanks from the bottom of my heart to this kind captain since these two words were toso simple.

"From the bottom of my heart" is a set phrase.

[I got the positionrough | passed] the interview with flying colors and got the job because the boss only gothad an elementary education, he was even unable to read the 26 English letters | the 26 letters of the English alphabet, and both of us were satisfied with each other.

I promised the boss I willould master the specified (specific?) and necessary vocabulary in a very short time.

“The specified vocabulary” means somebody specified (told you) exactly which words you needed to learn. Maybe you mean “specific” instead of “specified.”

When foreign freighters or cargo ships arrived at a Shenzhen port ( there are three ports there), my boss and I would get on the ship and ask for some business, t. The deals were all up to the captain.

I assume you mean there were three ports In Shenzhen, and you went to one of them.

They called us as ship chandler.

In most cases, they would reject us because their company had signed a long-term agreement with some big ship chandler in Guangzhou, theyand they had usually faxed a list of all required products to Guangzhou several days agoprior when they prepared to enter the harbor.

We only supplyied something that they had forgotten to list on the fax, which was also a big profn opportunity for us to earn a big profit, however.

We sold fresh vegetables, fruits(s), frozen meats(s), cement, and even condoms to the ships.

It would be more natural to use the uncountable forms of “fruit” and “meat,” unless you want to emphasize that you sold several kinds of each.

We musthad to visit the port every day to look for business and generally got a deal only about once a week, yet it was enough for us.

I remember the first time when I visited a captain from Israel, I couldn't understand the meaning of "cement" and "coke", h. He didn't laugh at me and explained them thoroughly to me.

At the same time, my boss looked at us radiantly with a smile, he was contentedly watching how hard I was trying to work, he didn't knownot understanding a word aboutof what we were discussing.

I sincerely want to show thanks from my heart to this kind captain since these two words were too simple | were so basic that I should’ve been expected to know them.

I got the position with flying colors because the boss only gothas an elementary education, h. He was even unable to read the 26 English letters, and b. Both of us were satisfied with each other.

I promised the boss I will master the specified and necessary vocabulary in a very short timequickly.

When foreign freighters or cargo ships arrived at the Shenzhen port ( there are three ports there), my boss and I would get on the ship and ask for some business, t. The deals wereould all be up to the captain.

What do you mean by “there are three ports there”? It seems out of place

They call us as ship chandlers.

In most cases, they would reject us because their company had signed a long-term agreement with some big ship chandler in Guangzhou, and they usually had (already) faxed all required producdocuments to Guangzhou several days ago when they were prepareding to enter the harbor.

Adding “already” would make this sound better.

We only supply somethings that they had forgotten to list on the fax, which was also(still?) a big profit for us, however.

“However” sounds out of place here. Is this close enough to your original meaning?

We must visit the port every day to look for business and generally only got a deal only about once a week, yet it was enough for us.

I remember the first time when I visited a captain from Israel, I couldn't understand the meaning of "cement" and "coke", he didn't." Instead of laughing at me and, he explained them thoroughly to me.

At the same time, my boss looked at us radiantly with a smile, h. He was contented watching how hard I was trying to work, and he didn't know a word aboutof what we were discussing.