There are many explanations on run-on sentence in OG, I hope to get more detailed knowledge about it. Thanks a million.

10. However much United States voters may agree that there is waste in government and that the government as a whole spends beyond its means, it is difficult to find broad support for a movement toward a minimal state.

(A)  However much United States voters may agree that

(B)  Despite the agreement among United States voters to the fact

(C)  Although United States voters agree

(D)  Even though United States voters may agree

(E)   There is agreement among United States voters that

A is the best choice. Choices B, C, and D incorrectly omit that after agree; that is needed to create the parallel construction agree that there is waste . . . and that the government... spends. Choice E, though it retains that, is grammatically incorrect: because E starts with an independent rather than a subordinate clause and separates its two independent clauses with a comma, it creates a run-on sentence with no logical connection established between the halves. In B, the agree­ment ... to the fact is unidiomatic, and B, C, and E alter the sense of the original sentence by saying that voters agree rather than that they may agree.

71. The original building and loan associations were

organized as limited life funds, whose members made monthly payments on their share subscriptions, then taking turns drawing on the funds for home mortgages.

(A)  subscriptions, then taking turns drawing

(B)  subscriptions, and then taking turns drawing

(C)  subscriptions and then took turns drawing

(D)  subscriptions and then took turns, they drew

(E)   subscriptions and then drew, taking turns

The sentence speaks of a sequence of actions in the past:

shareholders made their monthly payments and subsequently took turns drawing on the funds. Choice C, the best answer, uses parallel past-tense verb forms to express this sequence. Choices A and B violate parallelism by using taking where took is required. The wording in D results in a run-on sentence and does not specify what the members took turns doing. Similarly, E does not specify what the members drew, and taking turns produces nonsense when combined with the rest of the sentence.

263. In A.D. 391. resulting from the destruction of the largest library of the ancient world at Alexandria, later generations lost all but the lliad and Odyssey among Greek epics, most of the poetry of Pindar and Sappho, and dozens of plays by Aeschylus and Euripides.

(A)  resulting from the destruction of the largest library of the ancient world at Alexandria,

(B)   the destroying of the largest library of the ancient world at Alexandria resulted and

(C)  because of the result of the destruction of the library at Alexandria, the largest of the ancient world,

(D)  as a result of the destruction of the library at Alexandria, the largest of the ancient world,

(E)   Alexandria's largest library of the ancient world was destroyed, and the result was

D, the best choice, uses the idiomatic as a result o/and conveys information unambiguously. In A, the phrase that begins resulting from cannot properly modify later genera­tions. The word order of the largest library of the ancient world at Alexandria generates ambiguity: one possible read­ing is that the ancient world was located at Alexandria. Choice B is incorrect. Although an "-ing" verb such as destroying can sometimes act as a noun, in this case the usage is strained. Again, at Alexandria is ambiguous (as in choice A). Choice B also uses resulted ungrammatically and produces a run-on sentence (In A.D. 391, the destroying... resulted and later generations lost). In C, the phrase because of the result of is unidiomatic as well as redundant. The structure of E illogically suggests that there was more than one largest library of the ancient world and that only Alexandria's was destroyed. Furthermore, the result was should instead be the result was that.