Select all that apply. For the evidence stated in each sentence, which sentences use a correctly formed modal perfect for deduction about the past?
The badge log shows an entry, so someone must have unlocked the lab.✓Correct answer
The untouched dust shows that the technician must had moved the cabinet with exceptional care.
The tunnel was sealed all week, so the fox couldn't have entered through it.✓Correct answer
The path is spotless, so the muddy walkers mustn't to have returned this way.
Explanation
The badge log supports must have unlocked, and the week-long seal supports couldn't have entered; both use a modal followed by have and a participle. Must had moved replaces have incorrectly, while mustn't to have returned inserts a forbidden to after a core modal.