单词拼写练习： 1. Madame Curie devoted herself to s______ research. 2. Cholera was such a d_____ disease that many people died of it. 3. After they had studied for years, they a_____ with certainty that they found out the reason. 4. I think AIDS can be d________ by man in a few years’ time 5. Many people are in hospital because of the p_______ water.

cientific

eadly

nnounced

efeated

olluted