Manhattan GMAT 5th editon Chapter9 P152
it says The GMAT deems COMPARED TO and COMPARED WITH as the same. So I don't understand why the sentence "Compared with a horse, however, a zebra is very hard to tame." is right while the other one "When compared to horses, zebras are vicious." is wrong?
is it because of When?
what if I change it to As?
is the construction "As [past participle], [subject]..." correct?
For example, "As discussed, the meeting will be postponed to tomorrow."