The US and China are discussing slashing tariffs on certain goods, including on American energy and agricultural shipments - a potential sign the leaders’ summit next week will lead to an extension of the one-year trade truce.The meetings between the two sides are also likely to result in an agreement to lower duties on Chinese inputs for manufacturers, according to people familiar with the matter. The moves are expected to be carried out under an earlier plan for reciprocal tariff cuts on roughly $30 billion in trade.