Explain the words in bold. You can use your dictionaries
al reference resources. : boarded , attention, closest , extremely, exploring , rush hour , aiming​

boarded - get on or into

attention - notice taken of someone or something; the regarding of someone or something as interesting or important.

closest - a short distance away or apart in space or time.

extremely - to a very great degree; very.

exploring - in order to learn about or familiarize oneself with it

rush hour - a time during each day when traffic is at its heaviest.

aiming - point or direct (a weapon or camera) at a target.