Why can't she drive a car?
She isn't old enough to drive a car / She is too young to drive a car
Why couldn't they solve the puzzle?
It was too difficult / it wasn't easy enough
Why couldn't he pick up the box?
It's too heavy to pick up / He's not strong enough to pick it up
Why couldn't he do her homework?
He was too tired / She hasn't slept enough
Why couldn't he make the speech?
He was too shy to talk / He wasn't confident enough to talk
Why did they lost the singing competition?
They don't sing well enough / They sing too badly
Why did I lose the game?
You're not good enough / fast enough / You're too slow
Why did he get a bad mark in her exam?
She didn't study hard enough / She was too lazy
Why can't she swim?
It's too cold to swim / The water is not hot enough
Why didn't he go to school today?
He didn't get up early enough / He got up too late to go to school
Why didn't she buy the jacket?
It was too expensive / She didn't have enough money