Now, we not only no longer import them--we export them in large quantities. That not only saves foreign exchange, but earns a big sum of it instead.
「以前我們要花錢進口美國製或蘇聯製的人造鑽石，現在不但不必進口，還大量出口；也就是說，不但節省外匯，而且還賺進大筆的外匯。