4 Przeczytaj tekst. Wybierz poprawne uzupełnienie luk 4.1.-4.4. Zakreśl jedną z liter: A, B lub C.

Alexander Fleming was a Scottish scientist and is best-known for his 4.1. of penicillin. It happened in 1928 and was the beginning of the antibiotic revolution. Before Fleming achieved his success, he 4.2. lots of difficult, time-consuming research. my two who worked on the there for Medicine. He had toenicillin, and who two colleagues who worked on the therapeutic 4.3. of finally proved it was an antibiotic and not just an enzyme. Thanks to the three 4.4. lots of diseases have been treated and many lives have been saved.

4.1. A. theory B. discovery. C. design

4.2. A. has done B. would do C. had done

4.3. A. development
B. develop C. developed

4.4. A. results
B. researchers
C. predictions​