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.
... Today, however, we have membranes, and we don't yet understand how membranes fit into ...
... them, I chose to embrace and understand why ...