1. Step onto the wooden platform in this classroom.

2. Walk toward the raised platform to introduce yourself.
3. Step to the platform and recite the whold sentences in the passage.
4. Come onto the podium and intorduce yourself inclucing your school life.
5. You have to introduce yourself on the podium in/at the front.
[Can we use all the expressions in a classroom? Which one is better, podium or platform? In #5, can we use both 'at' and 'in'?]

A platform is an area of the floor, artificially raised above the level of the floor. A podium is a lectern or pulpit or some such piece of furniture or installation to hold one's notes/script, etc., and perhaps a microphone and or a lamp to provide light to read the speech or see the notes the speaker uses. It may or may not be on a part of the floor that is raised from the level of the rest of the room.

In number five, we can use "in" or "at" in casual language.

It's redundant to ask someone to recite (or translate) the sentences in a passage. If they are to translate or recite the entire passage, that includes all the sentences it contains.

I wouldn't use "podium" -- here's what they look like:

https://www.google.com/search?tbm=isch&q=podium&chips=q:podium,g_3:speaker&sa=X&ved=0ahUKEwiI9emAxvjZAhUHi6wKHcrTDoMQ4lYILigB&biw=1437&bih=716&dpr=1

A raised platform, as Reed has written, is simply a raised section in the flooring or a separate small structure that's been moved onto the floor at the front of the room. Those that I've seen are usually 8"-10" above the level of the floor.

Here's how I'd write these sentences:
1. Step onto the wooden platform in this classroom. (OK)
2. Walk toward the raised platform to introduce yourself. (OK)
3. Step to the platform and recite the whole passage.
4. Come onto the platform and introduce yourself, including your school life.
5. Please step up to the platform and introduce yourself. ("at the front" seems redundant unless there are more platforms in the room)

In a classroom setting, different terms can be used to refer to the elevated area where someone would stand to introduce themselves or give a presentation. Two commonly used terms are "podium" and "platform."

1. Step onto the wooden platform in this classroom.
- This instruction tells you to move onto the raised wooden surface in the classroom. The wooden platform is a generic term and could refer to any raised surface.

2. Walk toward the raised platform to introduce yourself.
- Similar to the previous instruction, this step directs you towards the elevated area where you will be speaking to introduce yourself.

3. Step to the platform and recite the whole sentences in the passage.
- This instruction specifies that you should go to the raised area, which could be a podium or platform, and read the complete sentences from the given passage.

4. Come onto the podium and introduce yourself, including your school life.
- Here, it explicitly mentions the term "podium." A podium is a small raised platform with a stand for holding notes or a microphone. It is commonly used for public speaking or presentations.

In regards to the use of "in" or "at" in step 5, both can be used depending on the context:
- You have to introduce yourself on the podium at the front.
- You have to introduce yourself on the podium in the front.

Both sentences are grammatically correct, but the choice between "at" or "in" depends on the specific layout and design of the classroom. Using "at" suggests that the podium is located specifically at the front of the classroom, while using "in" implies that the podium is within the area designated as the front of the classroom.