请问：The boy pretended to be working hard.中为什么用pretended而不用pre

请问：The boy pretended to be working hard.中为什么用pretended而不用pre the boy pretended ( )when his mother entered.括号中为什么填 to be r 1.When the boss came,she pretended to be working hard . He pretended to be working hard when his mother entered his He pretended to be reading a book 中为什么用be reading she pretended not to see me when i passed by这里为什么用not to 而不用 the boy pretended to be reading a book when the teacher came But she had to lie to the company and pretended to be a man he prevented /promised/protected/pretended to study hard alt The child pretended to (not to be listening) what his mother 英语翻译The girl pretended to be afraid and said,“I had to wash You perfect disguise,I can only pretended to be unconcerned.