all of a sudden，up and down，look out for，turn into，fly off，move on，in time，have yet to
（1）What made us frightened was that the car crashed into the tree when one of the wheels

flew off

flew off

.
（2）One of my middle-school teachers told me that I was a stone with sharp edges，but that I would

turn into

turn into

a smooth river stone as I grew older.
（3）Alex paced

up and down

up and down

the room within the hours of waiting for the result，looking worried.
（4）This is a great place for camping but you have to

look out for

look out for

snakes and spiders- Australia has some of the most dangerous in the world.
（5）You've been working on the project for the past two years and

have yet to

have yet to

take a vacation.
（6）Although she admits it is a difficult task，she has accepted it and

moves on

moves on

.
（7）When the powerful earthquake struck and all lights went out

all of a sudden

all of a sudden

，it seemed as if the world was at an end.
（8）At one time，I was upset about my poor English，but my teacher often said to me， "Keep working hard，and you will make progress

in time

in time

."