(1) Penicillin, one of our most important drugs, come from mold. (2) Alexander Fleming discovered it in England—by accident! (3) In 1922, Fleming was trying to figure out how to kill bacteria that caused diseases. (4) He has a cold and his nose is runny. (5) When he picked up a lab dish, some mucus from his nose dripped into it. (6) He seen that the mucus killed the bacteria growing in the dish. (7) By accident, he had made an important discovery. (8) It made him want to keep searching.

(9) In 1928, Fleming piled some lab dishes in a tray of liquid chemicals. (10) The chemicals would sterilize them. (11) But some of the dishes didn’t get covered by the chemicals. (12) Later, he noticed that mold had growed on one of the dishes. (13) The mold had killed the bacteria!

(14) The importance of Fleming’s discovery wasn’t realized right away. (15) It wasn’t until about 1940 that penicillin became widely used in medicine. (16) Since then, penicillin has cured some diseases that once killed millions of people.

(17) Fleming was very lucky. (18) But he wouldn’t have succeeded if he hadn’t been working hard on experiments anyway. (19) His discoveries was a combination of luck and hard work.

Which sentence has an action verb?
Sentence 2
Sentence 4

Sentence 17

Sentence 19