∠F and ∠E . . . already listed in the problem statement, so may not be considered an "other pair"
Step-by-step explanation:
∠C and ∠F are vertical angles, so are congruent. Then any angle complementary to one of those will also be complementary to the other.
Likewise, ∠B and ∠E are vertical angles and congruent. Any angle complementary to one of them will also be complementary to the other. Here, ∠E and ∠F are listed as complementary, so we know ∠B and ∠F will be also.
