什么是酶的体外定向进化，原理及一般流程。
You are the Cisco Network Designer in Cisco.com. Which of these is a Layer 2 transport architecture that provides packet-based transmission optimized for data based on a dual ring topology?（） [" DynamicTrunking Protocol"," Resilient Packet Ring"," Synchronous Digital Hierarchy"," Coarse Wave Division Multiplexing"]
论述“反者道之动”思想。
器官移植选择受体时道德方面的考虑包括（）。 [" 医学标准"," 社会价值"," 预期寿命"," 移植成功的可能性"," 经济能力"]
下列选项属于学习的是（）。 ["每天跑步","视力下降","装修房屋","不怕见生人了"]
某活塞式压力计的砝码丢了几块，能否用相同规格的另一台活塞式压力计的砝码代用？
