When he ______ the front door, he found his keys were nowhere.
Is it the book that ________ people of all ages ______ became the best-seller last year?
The president _________ at the meeting, _________ by his secretary.
As a matter of fact, this is just as ________.
-– David has made great progress recently. –- _________, and ________.
The only _______ to living in the countryside is the inconvenient transportation.