As we know, penicillin became the greatest drug of the 20th century, ______ millions of lives.
Not until the next morning _____ how serious the situation was.
The education reform plan took one year and nine months to draw up, _____ public opinions were called for,
If Tom _____ my advice, he wouldn't have lost his job.
While _____ to foreigners, you must try to make yourself _____ by using body language if necessary.
—Wow, so many books here! How can you find the one I need? —Yhat’s easy.The books are _____ by subject.