______I am concerned，the price of the computer is much too high，so I can’t afford it.

A．As long as

B．As far as

C．As well as

D．As often as

为便于计算机识别记录的各个字段，每个字段都设有字段标识符，下列哪个字段的标识叙述是正确的（）

A.TI是题名的标识符

B.AB是关键词的标识符

C.AU是摘要的标识符

D.AF是著者的标识符