Which sentence does not contain any errors in comma usage? a. her dog however, weighed over 40 pounds. b. everybody came to the wedding, of course. c. mom's recipes on the contrary, avoid salt. d. in fact chicago does have an elevated railway system.

What task did the surveyors do? a. they studied the landscape to determine the most direct route for building a road. b. they designed treadmills that lifted blocks of stone to where they were needed. c. they dug trenches and filled them with sand, concrete, and large blocks to form a road.