I reviewd both the ACT and SAT reading/english. The SAT requires more critical thought and has words in context, which the ACT does not. Im an adult, so this is different for most kids, but I found some of the questions on the ACT to be so obvious, I thought they were trick questions. You need to know the same English rules for both. But, as others have pointed out, the ACT requires very quick reading, so lots of practice would help to get the timing down. Have her try both.