Vctory:

You will learn faster if you post only a few sentences of your diary at a one time. Then you can discover where you have the most problems, do some concentrated study, and practice until you can write more perfect English.

Here is your first sentence:

As I need to improve very much in my English or I won't be able to handle the unified exam in the end of this year.

This is not really a sentence, because you have started it with a subordinating conjunction, (as) and there is no main clause.

Here are the 2 clauses:

(1) As I need to improve very much in my English

(2) I won't be able to handle the unified exam in the end of this year.

The clauses are joined by a coordinating conjunction (or), which makes them equal. So you have written 2 subordinate clauses, which does not make a sentence. Every sentence must have an independent (main) clause.

Here are 3 ways to write this correctly.

a) Make it a conditional construction; an if-clause, followed by the main clause.

If I do not improve my English, (if-clause) I won't be able to handle the unified exam at the end of this year.(main clause)

b) Use "unless" instead of "as", and do not use "or". The best form is to swap the 2 clauses, but either order is OK.

I won't be able to handle the unified exam at the end of this year (main clause) unless I improve my English. (subordinate clause).

c) Make the first clause the main clause by deleting the subordinating conjunction. The second clause will be a subordinate clause, introduced by "so that"

I need to improve my English (main clause) so that I will be able to handle the unified exam at the end of this year. (subordinate clause).

Here is your second sentence:

So that I need to write something in English.

You have made the same mistake, introducing the sentence with a subordinating conjunction - "so that". It is not a sentence, it is a fragment. There is no main clause.

You can fix this by using a "conjunctive adverb" instead of the subordinating conjunction.

Therefore, I need to write something in English.

You can also use a coordinating conjunction

So I need to write something in English.

There are other mistakes in the rest of your paragraph. But first, you need to study the connecting words in English so that every sentence you write will have a main clause. The types of connecting words are: coordinating conjunctions, subordinating conjunctions, and conjunctive adverbs. Please study your English textbook on this subject. Then practice writing sentences that use these words. You can post them here for review and suggestions

Also, this article is a good review of these words.

I had posted my reply with mistakes and comments highlighted. I am wondering where that thread had disappeared to. Basically, it pointed out the same thing.