If you _____ to something different, for example to a different system, task, or subject of conversation, you

change to it from what you were doing or saying before. [ ]

A. switch

B. appeal

C. submit

D. adapt

科学研究机构和学校，以科学研究和教学为目的，在合理数量范围内进口国内不能生产或者性能不能满足需要的科学研究和教学用品，免征进口关税和进口环节增值税，照章征收消费税。