The question seems somewhat incomplete. It would have been better if the values of exports and imports for each category were provided. Also, the information on what is included in each of these categories would have helped better answer this question.
From the given information, one can see that same or similar types of products dominate both the lists. For example, Computers and Electronics occupied the top slot in Imports and also the second slot in exports. Transportation equipment and chemicals show similar placements in both the imports and exports listings. Now, one should note that United States spends a lot of capital in research and development and manufactures or develops high-end products. Thus, combining these factors, it would appear that US is importing raw materials and exporting high-end commodities. For example, US may import a lot of computer and electronics components (from countries such as China, Malaysia, etc.) and export proprietary materials such as Software (say, operating system, security software, office productivity suite, etc.), laptops, etc. Similarly, it may import crude oil and export products of oil refinement process.
Thus, it seems that US has comparative advantage in value addition by refinements or technical superiority and uses it to manufacture and export high value commodities.
Hope this helps.