有关脑血栓形成CT扫描，下列描述正确的是()

A．发病在24小时内，脑CT扫描多数仍显示正常

B．发病72小时后，绝大多数能显示出大脑半球的梗死灶

C．发病第5～6周病灶为等密度影

D．发病3天以上至5周左右，病灶区可出现增强现象

E．发病5周以后，大梗死灶呈长久性的低密度影，边界清楚，无占位效应及增强现象

During her childhood Susan read a lot about Chinese history, from which she _________ greatly in her work in China now.

A．observes

B．recovers

C．recognises

D．benefits