In those days, we had no phones, so we have to keep in touch _____ writing often.
In the 21st century, all nations must take their __________ of responsibility for the global safety.
-I wonder if you could __________ me a little time to help with my English tonight? -__________. I have no extra work to do anyhow.
While you were out, you should keep your doors and windows __________.
Not recognizing me at first,__________.
-It's too cold now. Would you mind my __________ the window? -__________. Go ahead.