Advantages: Teachers should encourage their students to question everything.

I remember those days in high school where I taught biology, all my students never missed even one session through whole semester because they found my class different from others. My class was different since I made my students to ask everything that they needed to know, so they were so excited to be in my class. I do believe that it is necessary for teachers to encourage students to question in order to achieve more knowledge, constantly participation in class, and have more fun.

First, most students need to gain more knowledge and information in their class by asking their teachers about many subjects. If teachers try to encourage their students to question, they help students improve their knowledge. For example, my sister Math teacher, who is like strict teacher, never allow them to ask more question, so my sister has to face many struggle to solve the problems without her teacher's help.

Second, teachers may contribute to increase their students 'participation in class if they are interested in the students' questions. We always see many students who get detention because of their unexcused absents. They don't want to take their class which is always the same, so they need to be active by asking various question which turns in their enthusiasm to continue their education.

Third, students enjoy their time in class if they have a chance to ask whatever that matters for them. They want have more fun, and if their teacher doesn't allow them to feel free to ask, they couldn't feel happy. It is true that teacher should understand that having fun in class is always part of education; therefore, they have to let their students ask what they need.

Finally, it is a fact that students wants to obtain more knowledge, and enjoy their time through their participation in the class which can be provided by their teachers. Teachers should encourage their students to ask their question to take all those advantages that are mentioned.

For paragraph two, I wanted to example my sister's teacher not my sister; however, your correction seems easier to follow.
Morover, is that ok if we use infinitive verb after help? for instance, they help students to improve..
bahareh

Yes! That is a good way to write it. You can also omit the "to" if you prefer:
They help the students improve.

That first sentence is a run-on sentence. I see that Annika fixed it by adding a conjunction ("and"). That is a good idea! You can also just separate them into 2 sentences:

I remember those days in high school where I taught biology. All my students never missed even one session through whole semester because they found my class different from others.

And then we can improve the swiftness and clarity of the sentence:
I remember those days in high school when I taught biology. All my students had perfect attendance throughout the whole semester because they found my class different from others.

Great job here... I like the essay, but the last sentence does not seem very strong:
Teachers should encourage their students to ask their question to take all those advantages that are mentioned. too simple and obvious! But this essay is well-written.

:-)

Thankyou so much Kevin , and I will try to write more simple sentences rather than writing complex one.
Your sugestions always help me write better.
bahareh