The key answer of exercise Grammar 4
The key to exercise solutions in chapter 08 - Language focus 1 for the textbook Cutting Edge Upper-Intermediate - Student's Book with authors Sarah Cunningham, Peter Moor and Jonathan Bygrave from Pearson Education
Question
Why is can correct in 8 but not possible in 7 in the website?
Answer
Because we don't use can to talk about deduction in this way.