Although Fleming discovered Penicillin, it was over a decade ______ someone else turned it into the great drug of the

Who is ________ English teacher?— Well, it’s Mrs. Green. She teaches ________ English very well.

______is now no doubt ________ global warming is a security threat to us all.

“________ give up (放弃), then you can be successful.”

Eric, are your parents angry about your English in this exam?—Oh, of them is angry. They just told me to get better grades next time.