Tom and Mary don't seem to understand why they're not supposed to do that.
- Tom and Mary don't seem to understand why they aren't supposed to do that.
Tom and Mary don't seem to understand why they aren't supposed to do that.
- Tom and Mary don't seem to understand why they're not supposed to do that.
It's usually easy for Norwegians to get what Swedes are saying.
- It's usually easy for Norwegians to understand what Swedes are saying.
If Tom had been speaking French, I would have been able to understand him.
- If Tom had been speaking French, I would've been able to understand him.
... So we try to understand what happened, and we should ...
... need not only to understand which tool in the tool box is ...