Listen carefully and fill in the missing informati...
Listen carefully and fill in the missing information. 音频2 Drug development is the process of bringing a new pharmaceutical drug to the market once a lead 1_____ has been identified through the process of drug discovery. It includes pre-clinical research on 2_____ and animals, clinical trials on humans, and may include the step of obtaining regulatory approval to market the drug. The full cost of bringing a new drug to market – from discovery through 3_____ trials to approval – is complex and controversial; typically it is hundreds of millions or billions of U.S. dollars. Candidates for a new drug to treat a disease might theoretically include from 5,000 to 10,000 chemical compounds. On average about 4_____ of these will show sufficient promise for further evaluation using laboratory tests, mice and other test animals. Typically, about 5_____ of these will qualify for tests on humans. 1.