c

"I explained it, but it is pure conjecture whether he understood, or not."

"My friend told me there was something in the box, but I didn't know what it was yet. "

"My grandmother taught me how to bake cookies when I was a child. "

"It was an experience he would not soon forget."

"The science teacher conducted an experiment to demonstrate how plants grow in different types of soil. "

"The violinist was a master of her instrument."

"My sister is very helpful, especially when it comes to organizing things. "

"The increased sales of organic vegetables this year are witnessing a growing consumer interest in healthy eating. "

"The library offered an extension on the due date for the overdue books. "

"The verbs in sentences like "Do it!" and "Say what you like!" are in the imperative."

""Mr. Smith always uses the abbreviation 'etc.' instead of writing out 'et cetera'." "

"The school offered an alternative schedule for students who needed more time to study. "