对双层底内为燃油舱的区域，其内底板的厚度应不小于（）。
A.6mm
B.8mm
C.10mm
D.12mm
参考答案：B
My father has worked in this factory fifteen years. [ ]
A. for
B. since
C. before
D. in
干扰细菌细胞壁合成的抗菌药是（）
A.多黏菌素
B.氨苄西林
C.甲氧苄啶
D.诺氟沙星
E.替硝唑
