This sentence misuses a colon: there is no second clause that explains an element of/the whole clause. There is no need for additionally punctuation whatsoever. The correct answer is, "The school completed the library in 1998."

This sentence misuses a colon. Colons are used to join two independent clauses when the second clause clarifies some element of the first clause. While these two clauses are related, the second one does not really clarify why the products are being released or anything about the companies. Instead, the second clause provides some additional information. A semicolon would be more appropriate after the word "year." A comma is also necessary before the "and" since the clause "others will flop in the markets" functions as an independent clause. The correct choice is, "Companies release many new products each year; some of them will be successful, and others will flop in the markets." 

This sentence misuses a comma. This sentence combines two independent clauses together without the use of a conjunction. The second clause, however, clarifies elements of the preceding clause: it tells us what Kim's dream job is. A Colon is most appropriate after the word "job." The correct choice is, "Kim landed her dream job: she would be head of marketing." Note that a period could be correct, but the choice given does not capitalize the word "she," which follows the period, thus making this choice incorrect. 

This sentence misuses a colon: colons are used to join two clauses when the second clause clarifies/explains either an element of- or the whole preceding clause. This sentence joins two related sentences without the use of a coordinating conjunction, so a semicolon would be the most appropriate punctuation for the sentence as-is, but that is not an option. The next best choice is, "Many people say that reading that book is useful for leadership and business, but Luis did not see the connection" since it joins the sentences together with a comma and "but."

Note that the comma would be inappropriate in this position without a coordinating conjunction, so the comma standing alone is incorrect. Additionally, the hyphen is misuses here because it is also used for clarification, which is not the function of the following clause. The correct choice is, "Many people say that reading that book is useful for leadership and business, but Luis did not see the connection. "

This sentence misuses a colon. Colons are used when joining two clauses together when the second clause explains the whole or an element in the first clause. This sentence is a simple sentence, so no punctuation of any sort is necessary. The correct choice is, "The internet has led to many changes in the way humans."

This sentence misuses a colon. The phrase "In Ralph's opinion" is an introductory phrase, explaining information necessary to the context of the sentence, but outside of the main sentence, grammatically. These types of phrases must be followed by a comma in order to separate them from the rest of the sentence. Colons, on the other hand, must follow an independent clause that does not end in with a verb. The correct answer choice is, "In Ralph's opinion, Rock is."

This sentence misuses a colon. Colons are used to join two related clauses when the second clause explains something about/the whole first clause. This is not the case in this sentence: the words "in order" and "to confirm" are part of the same clause. No punctuation is necessary. The correct choice is, "site in order to confirm that the development of the land was on schedule."

This sentence misuses a semicolon. The phrase "which started in 1929" is an example of a relative clause, which gives more information about its antecedent: The Great Depression. Any such phrase that occurs in the middle of a sentence must be introduced and completed with a comma. The correct choice is, "The Great Depression, which started in 1929, was a time."

This sentence misuses a colon. Colons are used to combine two clauses, but only when the second clause explains the whole/something about the first clause. The phrase "she decided to place it in her living room" does not explain anything about the carpet itself or why Tina loves it. Instead, a semicolon is appropriate after the word "carpet" since this sentence joins two related independent clauses without the use of a coordinate conjunction. The correct choice is, "her new carpet; she decided to place it."

This sentence misuses a colon. Colons are used to join two clauses when the second clause explains the whole/something about the first clause. The words "cars" and "in" are part of the same clause; however, so no colon should be used. This is a simple sentence, so no punctuation is necessary. The correct choice is, "The cars in the garage."