2. Rain check

A : I heard that the movie “ABC” will be released this Friday. Why don’t we go to the movies after we finish work this Friday (or Do you want to see a movie this Friday)?
B : I’d love to, but I have plans already (or I wish I could, but there is a staff dinner that day). Can I get a rain check?

3. Thigh(s)
These days, I am trying to lose some weight. However, I find it very difficult to lose some weight from my thick (heavy- this word is used in English when we are talking about your total weight, not just one area  Ex: I am very heavy and need to lose weight.  Incorrect: My stomach is very heavy so I need to lose weight) thighs.

4. Make it
A : Will you come to my party tomorrow? I really hope that you can (could is past tense and you are speaking a party that will happen in the future) make it.
B : Oh, James. I have to work overtime tomorrow. As you know (I removed well), the deadline for the project is coming soon. I’m afraid that I can’t make it.

5. Break
I think you are very exhausted, (added a comma) now. You need to rest (need some rest / need to take a break) right now.

6. There are no amenities (facilities) near my dormitory. Most of my colleagues left the dormitory and I think that (refers back to your first sentence)  is one of the reasons that they left.

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You used all of the expressions well. I made a few corrections but all of the sentences used the expressions correctly. 

I think writing sentences like this is a great way to practice you grammar and expressions. 

Teacher Beth