Solutions

Question

Leaching, the recovery of copper from the drainage water of mines, as a method of the extraction of minerals, it was well established as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria take an active part in the process.

 

Difficulty Level

Easy

Solution

Option C is the correct answer.

Option Analysis

Concept tested: Sentence fragment, modifiers, tenses.

 

A) This is a sentence fragment. Moreover, it uses the pronoun “it” which is ambiguous.

B) Sentence fragment.

C) Correct Answer

D) Inappropriate usage of “That” as it refers to minerals.

E) Wrong tense. We do not require past perfect tense.