My sister knows how to dance.
My sister / she can dance
My friend doesn't know how to ski.
My friend / he / she can't ski.
We know how to speak English.
We can speak English.
You know how to swim.
You can swim.
Mr Krabs knows how to play the world's smallest violin.
Mr Krabs can play the world's smallest violin.
One of my teachers knows how to knit.
One of my teachers can knit.
When my mom was 20 she didn't know how to dance.
She couldn't dance.
When we were kids, we didn't know how to walk.
When we were kids, we couldn't walk.
At first, Dua Lipa didn't know how to dance, but now she knows.
At first, Dua Lipa couldn't dance, but now she can.
When the Olsen twins were kids, they were good at acting.
When the Olsen twins were kids, they could act.
These bags are so heavy, I don't have the ability to carry them.
I can't carry these bags.
Marco learned how to drive a car until he was 34.
Before 34, he couldn't drive a car.
She's seven years old, but she CAN'T / COULDN'T read yet. Her parents are getting her extra lessons.
can't
I read the book three times, but I _____ understand it.
couldn't
James CAN / COULD speak Japanese when he lived in Japan, but he's forgotten most of it now.
could
I ____ understand the chapter we had to read for homework. It was so difficult.
couldn't
