Correct the following sentences for the kinds of writing errors outlined in CLUE Review Guides $1-20.$ These might include subject$/$verb agreement errors, incorrect or unclear pronoun reference, aggregate noun treatment, modifier errors, or sentence structure errors. Identify the type of error. $($Two marks for a perfect correction plus one mark for correct identification.$)1.$Barrels of oil, as a unit of measure, are hard to grasp outside the industry.Type of error: $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_2.$Not wanting to seem lazy, the report was added to Samanthas to$-$do list.Type of error: $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_3.$The junior clerk filled out the purchase order for one thousand light coloured folders.Type of error: $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$