单项选择题 These studies will yield valuable lemons ________.A) in which to save lives and protect propertyB) how to save lives and protect propertyC) in how to save lives and protect propertyD) about those to save lives and protect property

单项选择题 ________ exposure to dirty air can cause people suffer from some diseases.A) RaisedB) ProlongedC) ExpandedD) Enlarged

单项选择题 Visitors to England sometimes find the lack of public activities in the evenings （）.