You can write a paper characterizing the trade between the US and another country (China if you want).
Your paper could have the following sections:
(1) Introduction: Description of the objective of your paper and your main findings.
(2) Description of the most important traded products and the evolution of trade between these two economies. You can include two subsections:
(2.1) Recent evolution (last 50 years), and
(2.2) Current situation.
(3) Connect your previous findings with the theories covered in class. What theories are most appropriate to understand the patterns of trade between these economies?
(4) Conclusion: Summarize your main findings.
(5) References
(over 20 pages)