当父亲进来时 男孩假装正在读书。 ( pretend to be doing )The boy pretended to be reading when his father ca

问题补充：

当父亲进来时，男孩假装正在读书。 ( pretend to be doing )

答案：

>The boy pretended to be reading when his father came in.

考查动词短语pretend to do。pretend to do假装做某事，不定式可以是进行式，也可以是完成式。