1/4标准砖墙墙体厚度应为（）。
A.60mm
B.53mm
C.50mm
D.48mm
参考答案：B
The Smiths bought a new house, which was the of his neighbours.[ ]
A. envy
B. admire
C. respect
D. pride
已知Rt△ABC，∠C=90°，若已知b、c的长求∠A，则直接采用的关系式为______．
