The absence of such a provision made withdrawal technically difficult but not impossible. This makes it difficult, if not impossible, to modify the dependencies. These factors make it more difficult and dangerous to diagnose problems. This makes them extremely difficult to properly recycle. This makes re-work very difficult and at times impossible. Really way, way more difficult than we originally thought. Traders were often in particularly difficult positions. She cited the scene of trying to sing badly as very difficult. They are put in increasingly difficult battles. There may be difficult or painful swallowing. Tony finds this very difficult to believe. However, designing a divertor for a tokamak proved to be a very difficult design problem. Sales continue to increase making it difficult to meet demand. It is the oldest but most difficult figure skating jump. This is because of more difficult fabrication.