Madame Curie is believed ____ the radium.
A: discovering
B: having
discovered
C: to have discovered
D: to discovered
A: discovering
B: having
discovered
C: to have discovered
D: to discovered
举一反三
- Madame Curie is believed _________ radium (镭). A: discovering B: having discovered C: to have discovered D: to discover
- Madam Curie is believed ___ the radium. A: having discovered B: to discover C: to have discovered D: discovering
- The Vikings are believed ________America. A: to have discovered B: to discove C: in discovering D: to have been discovered
- By the year 2010, scientists probably ______ an effective treatment for cancer. A: will have discovered B: are discovering C: will be discovering D: have discovered
- The scientist ________ a new bacteria in 1912. A: discovered B: was discovering C: discovers D: have discovered