The postman usually uses a machine to divide the letters into two sorts.

Then the letters _____ from one place to another by car.[ ]

A. are taken

B. will take

C. are taking

D. take

当进口钢筋的国别及强度级别不明时，应首先按不同外形和标志分类，然后分批进行机械性能试验，并根据试验结果确定钢筋级别后，再用于主要承重结构的重要部位上。( )