FBI agents hide behind a tree to do a risky investigation.
Medical checkup. Also, investigation, inspection, review: (fiancial audit, smog check, check the condition of goods that roll off the assemby line, etc). Has the nuance of a test where something passes or fails.
to give thorough consideration to the topic. To investigate something thoroughly. Often said by politicians who don't want to give a real answer.
The detective TREE investigates the thrifty PERSON.