This book is written in such easy English so those with basic command of English can read and understand it.

A．so/that

B．such/as

C．so/as

D．such/as to

电能表转盘边缘应有长度约为转盘周长（）的黑色或红色标记。

A、2％

B、3％

C、4％

D、5％