Explanation

　　1.The correct answer is D

　　The error in this sentence occurs at (D), where there is an unnecessary pronoun. The pronoun “it” should be deleted so that the comparison is clear: one type of newt “grows to about seven inches,” and the other “grows to about six inches.”

　　2.The correct answer is D

　　The error in this sentence occurs at (D), where there is an inappropriate verb form. The infinitive “to achieve” is needed to parallel the infinitive “to use.”

　　3.The correct answer is D

　　The error in this sentence occurs at (D), where there is an inappropriate pronoun. The singular pronoun “that” is needed to refer to the singular noun “manner.”

　　4.The correct answer is A

　　The error in this sentence occurs at (A), where awkward phrasing and an unnecessary pronoun create a comma splice. The entire phrase “It depends on” can be reduced to “Depending on.”

　　5.The correct answer is C

　　The error in this sentence occurs at (C), where there is an improper idiom. In order to appropriately complete the correlative construction, the word “also” must be inserted after the conjunction “but.” This results in the correlative construction “not only…but also.” In addition, what follows “not only” must be grammatically parallel to what follows “but also,” so the word “but” should be changed to “but also because.”

　　6.The correct answer is A

　　The error in this sentence occurs at (A), where there is an improper idiom. The phrase “in addition to” is needed in place of “also.”