30
(A)on purpose
(B)at random
(C)in vain
(D)by chance

 It is believed that Michelangelo did this 30 , because it provided good profiles of David when seen from all sides. 

31 , Michelangelo sculpted雕塑；雕刻 with not only human anatomy解剖學, 解剖構造 and common imperfections缺點；弱點 in mind心里, but also with the viewing angle of the people on the ground.

It wasn’t until science and photography enabled配有（某種設備或技術）的；可以使用 us to look at David in various angles and heights was it discovered that David’s eyes weren’t “perfect.”

For non-technological viewing, David’s squinted瞇起眼看, 眼病, 斜視 eyes contribute貢獻，奉獻 to his stature聲望；聲譽, 高度 and posture姿態，儀態；姿勢 from all sides.

補充：

statue翻譯：（尤指石頭或金屬的）雕像，雕塑，塑像。

stature翻譯：聲譽, 聲望；聲譽, 高度, 高度；（尤指）身高。 

status翻譯：正式地位, （尤指在社會中的）地位，身份, 尊重, 尊重程度；仰慕程度；重視程度  

(C)in  vain翻譯：不成功的, 徒勞的；枉然的；無用的, 自私的, 虛榮的；自負的。
(D)by chance. ph. 意外地, 偶然