单项选择题
I don’t know who()America.
A.foundB.discoveredC.found outD.looked for
单项选择题 The government is promoting a ( ) against corruption and bribery.
单项选择题 The manager flew into ()when he heard that his secretary had disobeyed his instructions.
单项选择题 The question set by the teacher was so difficult that the pupils did not know how to()it.