I.单词拼写 1.After a few days' rest, she has_ recovered(恢复) her health.2.The progress of the society is based on_ harmony_(和谐). 3.At one time silk was__ reserved(保留) only for the Chinese emperor.4.I once got a chanceto__ observe_(观察) how a detective actually works. 5.We need to master this technology immediately (立刻),otherwise we will fall behind.