Read these sentences and fill in the gaps with 'could', 'can', 'couldn't', 'can't'.
1. Sally talk to customers yesterday as she was a bit nervous.
2. Before the nuclear disaster in the 1980's, people grow everything in their gardens.
3. Steve solve this problem now. He needs time.
1 couldn't
2 could
3 can't
1 couldn't
2 could
3 can't