The book __ by him is difficult __.

A．wrote; understanding

B．written; to be understood

C．writing; understand

D．written; to understand

下列哪些部位病变不影响光反射

A．视中枢损害

B．视辐射损害

C．外侧膝状体损害

D．瞳孔括约肌损害

E．视网膜病变