Madam Curie is believed ___ the radium.
A: having discovered
B: to discover
C: to have discovered
D: discovering
A: having discovered
B: to discover
C: to have discovered
D: discovering
举一反三
- Madame Curie is believed _________ radium (镭). A: discovering B: having discovered C: to have discovered D: to discover
- Madame Curie is believed ____ the radium. A: discovering B: having<br/>discovered C: to have discovered D: to discovered
- 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