下列哪一项与基托折裂无关 ()
A.基托太薄
B.未作加强或加强不当
C.基托材料强度差
D.基托的外形差
E.基托与黏膜不密合
参考答案:D
解析:基托折裂与基托的外形差无关。
It is _______ he often fails in exam_______ makes his parents worried about him. [ ]
A. because, that
B. that, that
C. 不填, that
D. what, that
取浓度相同的NaOH和HCl溶液,以3∶2 体积比相混合,所得溶液的pH 等于13,则原溶液的浓度为[ ]
A.0.01 mol/L
B.0.017 mol/L
C.0.05 mol/L
D.0.50 mol/L