Вставьте артикли, где это необходимо. 1) i`m in first form. my sister is in second form. 2) do you live in third house? 3) who likes fifth song? 4) dialogue five is interesting. lena, do you want to dialogue? nikita lives in room seven and roman lives in room ten.

1) I`m in ...the  first form. My sister is in ...the second form.
2) Do you live in ...the third house?
3) Who likes ...the fifth song?
4) ..---.. Dialogue Five is interesting. Lena, do you want to learn...the dialogue?
5)...--- Nikita lives in...--- Room Seven and...--- Roman lives in...--- Room Ten.

"Я в первом классе. Моя сестра во втором классе. 2) Ты живешь в третьем доме? 3) Кто любит пятую песню? 4) Пятый диалог интересный. Лена, хочешь поговорить? Никита живет в седьмой комнате, а Роман живет в десятой комнате."

Explanation and solution:
1) The only missing article here is in the second sentence: "My sister is in the second form." When talking about an ordinal number, we usually use the definite article "the" before it. Therefore, "the second form" is the correct answer.

2) The phrase "do you live in third house?" is missing an article. The correct form should be "Do you live in the third house?" Here, "the" is used to specify a particular house among others.

3) The sentence "Who likes fifth song?" is missing an article. The correct form should be "Who likes the fifth song?" Here, "the" is used to specify a particular song among others.

4) The phrase "dialogue five is interesting" is missing an article. The correct form should be "Dialogue five is interesting." Here, "Dialogue" is a countable noun, so it requires an article before it.

5) The sentence "Lena, do you want to dialogue?" is missing an article. The correct form should be "Lena, do you want to have a dialogue?" Here, "dialogue" is used as a countable noun, so it requires the indefinite article "a" before it.

6) The sentence "Nikita lives in room seven and Roman lives in room ten" is missing articles. The corrected form should be "Nikita lives in room seven and Roman lives in room ten." Here, "room" is countable, so it requires an article before it.