simple sentences

1.
They come from China(If they were here for holiday)/ They are from China.( if you mean it like that they nationality is chinese). He comes from America.
What do you think about it? Why she loves cooking?
They don't say anything about me. He doesn't smile.
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I will start to do my homework tomorrow. (If I decided just now) I am going to start doing my homework tomorrow.(If it is my plan for future)
In which time they will go to sleep?
She will not/ won´t(shortcut) leave the house.
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I told you the story yesterday.
How did he use the pen?
We didn't talk.

2.
I am here. He is there. You are beautiful.
Am I asleep? Does he know? Are they having a fun?
I am not a doctor. She is not his daughter. We are not students.
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I will be your language partner.
Will you be a sailor?
They will not participate in the concert.
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He was my boyfriend. We were the best friends.
Did he study at this college/university? Have you been a donor?
I was not here yesterday. They didn´t know anything about me.