— Dad,could you buy me a MP4 like this?

— Sure, we can buy ____ one than this, but ____this. [ ]

A. a worse, as good as

B. a better, better than

C. a cheaper, as good as

D. a more important, not as good as

在主、次梁受力筋下均应垫垫块(或塑料卡)，保证保护层的厚度。( )