A hundred years ago, people ___ use smartphones.
couldn't
could
When she was a baby, she ___ run.
couldn't
could
Last week, she ___ find her pencil.
could
couldn't
When she was a baby, she ___ only drink milk.
could
couldn't
Two days ago, we ___ go outside because of the heavy rain.
could
couldn't
In the past, she ___ ride a bike.
couldn't
could
When he was a teenager, he ___ play basketball all day.
couldn't
could
Last night, he ___ sleep because it was too noisy.
couldn't
could
Yesterday, the students ___ understand the difficult math question.
couldn't
could
When he was five years old, he ___ speak English.
couldn't
could
When he was young, he ___ eat ten hamburgers!
couldn't
could
