Bicycling is good exercise; ____, it does not pollute the air.
This is certainly the case, but ____ it is a mistake or not I don’t know.
Villagers often say our village is no longer ____ it used to be.
— ____ can I deal with such a situation?— Take ____ measure you think best.
The reason why I gave in is ____ if I didn’t.
No matter how fast we worked, ____.