问题补充：
Half of her time in the library.
A. spends on books
B. is spent reading books
C. has paid for reading books
D. is spending to read
答案：
A. spends on books
(答案→)B. is spent reading books
C. has paid for reading books
D. is spending to read
解析：句意：她的一半的时间都是花在在图书馆读书上。结合语境可知本句描述的是客观性动作，故用一般现在时态。主语是动作的对象，故用被动语态，选B。
