an unmanned aircraft/aircraft - not operated by people

we followed the bear's tracks in the snow - marks left by people or animals

idiom - to cover your tracks

cruel

I want to have my hair dyed(wash away)

my time management is poor

on the other hand, I often encounter some difficulties that I need to handle, I want to take time off

stressful situation; stressed people

go on/take personal/sick/maternity leave(get over illness)

former and latter; link, connect

chit-chat = informal chat

idle chatter/gossip/speculation

cellular data

laser: a beam of light

follow a pattern

a motor scooter;   scooter; electric cars/bikes; electronic devices-PCs, cell phones

former=ex

participate in = take part in