单项选择题
Domestic oil（）and gasoline prices are two important issues in the presidential campaign.
A.explorationB.exploredC.exploringD.explore
单项选择题 Vietnam has（）as the world’s third-biggest rice exporter.
单项选择题 Mr.Leach is on holiday and was not（）for comment.
单项选择题 （）that dieting is fruitless for people who think that they are too fat，the alternatives are fairly limited.
