Mr Obama's trip predictably failed to produce breakthroughs on either issue, though a lengthy joint statement outlined measures to step up co-operation on developing clean energy.

正如前期所料，这两个问题，在奥巴马此次访华之旅中难以得到任何突破性进展，尽管中美双方就共同研发清洁能源的措施草拟了一份详尽的联合声明。