15. They the institute five years ago.
(A) have entered
(B) entered
(C) had entered
16. Does the professor _ a lot of experience?
(A) has
Ο Ο Ο
(B) have
(C) had

Read the paragraph. in fact, teenagers contribute a great deal to their community. this is another reason why they must be taken into account when public policy is debated. over eighty percent of teens spend time volunteering at their schools and other organizations. this is an example of statistical analysis layering point of view outlining