Some simple sentences

1. 我喜欢中国菜。(I like Chinese cuisin).

2. 我在做饭。(I am cooking).

3. 这是一个中国杯子。(This is a Chinese cup).

4. 她买了冬天的衣服。(She bought winter clothes).

5. 我可以看一下你的书吗？(Can I take a quick look at your book?)

Please be kind enough to correct them! Thanks :-)

1. 我喜欢中国菜。(I like Chinese cuisin). 

2. 我在（做）菜。(I am cooking). 做菜、做饭 are synonymous, especially when there is no object in the given English sentence . Both of them means that you are preparing for a meal. 

3. 这是一个中国杯子。(This is a Chinese cup). 

4. 她买了冬衣。(She bought winter clothes). First, I agree with Typisss's answer, that's a good one.  I just want to add that if you were trying to be brief , "冬装" is a better substitute for "冬天的衣服" rather than "冬衣".

5. 我可以看看你的书？(Can I take a quick look at your book?)Again, Typi's answer is right. In a general question in Chinese, don't forget to complete the sentence with a proper modal particle. They are indicators that this sentence is raising a question.

Some simple sentences

1. 我喜欢中国菜。(I like Chinese cuisine).

2. 我在做菜。(I am cooking).

3. 这是一个中国杯子。(This is a Chinese cup).

4. 她买了冬衣。(She bought winter clothes).

5. 我可以看看你的书吗？(Can I take a quick look at your book?)

Please be kind enough to correct them! Thanks :-)