Q1. Choose the option that makes the sentence grammatically correct. The candidates waited ___ the examination hall ___ two hours before the document verification began.
Explanation
Use "in" for being inside an enclosed place and "for" for a length of time. The cues are "the examination hall", an enclosed place, and "two hours", a duration. Only "in / for" satisfies both cues; "on" is wrong for a hall, "at" does not show being inside it, and "since" needs a starting point such as "since 10 a.m." Therefore, the correct sentence is: "The candidates waited in the examination hall for two hours before the document verification began."
