Due to high costs, the program was never fully implemented.由于成本高，这个计划从未得以全面实施。Bone marrow transplants are a controversial procedure, primarily because of the high costs involved.骨髓移植是一项具有争议的手术，主要是因为其价格昂贵。The work is slow and dangerous, whence the high costs.这工作费时而又危险，因此费用很高。