Transport
third wheel / fifth wheel
an unneeded, extra person
put something under the microscope
to examine a situation very closely and carefully:
this won't hurt a bit
understatement
recharge your batteries
rest after being very busy, so that you will be ready to star working again
put the pedal to the metal / floor it
to go faster
a light bulb went off / on in my head
a person suddenly understands something or has a great idea
you're just going to feel a little pinch
it will be a bit painful
it's like riding a bike
If you learn something, you never forget it.
around the clock
all day and all night