South Africa’s government will tell President Donald Trump’s administration that its review of a preferential trade agreement that could put as much as $2.4-billion in exports at risk is premature and potentially damaging for both economies. The US Trade Representative will start public hearings on Thursday to review the nation’s duty-free access to the US market under the so-called Generalized System of Preferences, its oldest and largest trade-preference program for the world’s poorest economies.