Decode Japanese

I am so excited today. In the afternoon, I am reading a Japanese cookbook, I found some sentence that combined together, and I finally decoded it. I am a person like to ask why, why this, why that. Whenever I saw a phrase, I will try to break it down into component, to find out why this phrase mean this.

For example, I found this today.
ペンで書かなければなりません - Means It is not OK if you don't use pen to write.

The cookbook told me when never you want to express this, you can use this kind of sentence.
ペンで書か - なければなりません
First part of the sentence is make up from a verb. ペンで書く - Use(で) pen(ペン) to write(書く) , and the second part of the sentence carry out the meaning "It is not OK if you don't". OK, this is where I start puzzled.

I tried to find out why and I got the answer:
なければ is from the word ない, なければ is the Possible Form of ない, which mean "If don't". なりません is from the word 成る, なりません is the Negative Form of 成る, which mean "It is not OK". So, if you combine together, you will get the meaning "It is not OK if you don't". :D

As a conclusion, whenever there is a phrase, there must be a hidden meaning that make up from a very basic term/word. I will keep on find out why for other phrases.

Possibility is everywhere.