After serving his apprenticeship as a toolmaker, he became a manager.结束了工具匠的学徒期以后，他当上了经理。He served his apprenticeship with Bob.他跟鲍勃当学徒.He is not yet out of his apprenticeship.他尚未满师....
Chitin synthase is the important enzyme that converts UDP - GlcNAc to chitin.摘要几丁质合成酶是生物合成几丁质的关键物质.Chitin, chitosan are recycling natural polymers with abundant and excellent properties.甲壳素 、 壳聚糖是可再生的天然高分子化合物,来源丰富、性质优良.C...