Some more observations: From Advanced Practice Exercise,
5- (Answer given is C) - It can only be C, if you remove 'for' from the end or D if you add that to connect the restrictive clause.
33- (Answer given is A) - although none of the choices seem right, don't you think the answer should be ... "would work on it this weekend instead of... "
39 - (answer given is B) - Is this really a logical conclusion since we used 'must', sound more like an obligation and hence 'should', should have been used.. don't you agree ?
42 - (answer given is D) - It can't be D since the pronoun at the start of D 'his' has no subject/Noun (misplaced modifier).. Don't you think the answer should be 'A', the subject is being introduced and is a complete sentence with proper pronoun linkage.
Let me know..