1.   Before the class begins, mix the cornstarch and water together in a large mixing bowl.

2.   Classes began soon after we enrolled.

3.   Fees are to be paid before classes begin.

4.   Most classes began with a discussion of readings that Gordon had distributed the week before.

5.   After the class began, most of what the professor said escaped my ears and I left as soon as the lecture ended.

6.   Unfortunately, the professor appeared and the class began.

7.   And fall classes will begin.

8.   Arranging for adults to supervise breakfast before classes begin is one problem.

9.   As the children became immersed in their projects, the teacher said she could see a difference since the weekly classes began more than a year ago.

10.   At the request of school officials, police officers were posted in the high school parking lot as classes began Tuesday.