混凝土抗压强度评定按TB10425-94进行，采用标准偏差已知法时试件取4组，采用标准差未知法时试件取5组或5组以上。
参考答案：对
There ______ any pork in the fridge, but there ______ 3 bottles of fruit juice. [ ]
A. isn't, are
B. isn't, is
C. aren't, are
D. aren't, are
牙槽突骨折的特征性表现是（）
A.伴牙缺失
B.伴有唇和牙龈的肿胀和撕裂，撕裂口与牙相对应
C.咬合错乱
D.摇动损伤区某一牙时，邻近牙及骨折片随之移动
E.伴牙折或牙脱位
