They’re arguing on who, on earth, is known for the great discovery        penicillin, an effective bacteria killer.

Be careful how you _____ that jug, it will break very easily.

---Mary was asked to do something important.---It doesn’t matter. Let’s        the work where it is left off.

The mother opened the door quietly so as not to       the sleeping baby.

 I          Peter at once although I hadn’t seen him for 10 years