showing or expressing action; engaged in activity
The boys actively worked in charities.

someone who is fully grown up
adults are expected to set a good example for children.

a situation where two things share a relationship with each other
Protein is an essential part to a healthy diet as well as an important nutrient for muscular development.

to believe something or someone to be
He is considered to be the country's authority on Middle East policy.

not serious, casual in nature or attire
On Fridays we have an informal dress code at work.

nor yet, no more
Bob can't go, and neither can I.

to note with one's senses
The teacher observed the new students in the class before beginning the lesson.

to take place; happen
It never occurred to her to call her parents when her plane got delayed.

an organized activity undertaken by a student or a group of students
The class was divided into to groups of four, and each group was given a project to complete by Friday.

a specific instance or state of affairs
Sue was in an uncomfortable situation when her parents and her teacher met to talk.