什么叫冷铆？
简述水流流速、颗粒大小与碎屑物质在流水中搬运与沉积的关系。
马克思设想共产主义高级阶段（）。 ["按劳分配","按资分配","按需分配","按生产要素分配"]
装配式整体结构中的不承受内力的结构和拼缝可采用砂浆浇筑，其强度等级不应低于（）。 ["A.M5 ","B.M10 ","C.M15 ","D.M20"]
Under which two circumstances should Spanning Tree Protocol be implemented？ （） [" to ensure a loop-free topology"," to protect against user-side loops"," when a VLAN spans access layer switches"," for the most deterministic and highly available network topology"," because of the risk of lost connectivity without Spanning Tree Protocol"]
行政诉讼中，什么情况下，被告可以补充证据？
