OKAY.
26. [Like his other cookbooks], in his new book Chef Louis offers lengthy explanations of what he considers to be basic cooking principles.
The bracket is wrong. So basically you can't modify a preposition phrase? Just explain PLEASEE!!!
25. The Food and Drug Administration has overlooked the dangers of (some) drugs that seemed (perfectly safe) (until) long after they (are) in general use. (No error)
It's (are). Is it because it should be (were)?