English is the most important course I need to master

It is my extended head.

I must have a perfect English.

English is so important. Too important. Extrememly important. I see no doubt for it.
English is the most important.

Learn English. Learn more and more and more.

It is so important to get the international standard.
It is the first thing to get the international standard.

I aim for the International standard. That is the first criterion for human resource.
It is the most important thing to play at the international level.