Question 38 - Reading and Writing Practice Test for the PSAT/NMSQT Exam

What punctuation should be used in the underlined portion of the passage provided, according to Standard English conventions?

California has been waiting for “the big one” for years, and the US Geological Survey (USGS) suggests a major earthquake is likely to hit the state before 2032. A major earthquake greater than 6.7 will likely hit the San Francisco Bay region in the next 30 years based on fault lines and previous earthquake activity however, a large earthquake could happen along fault lines in Southern California as well.