单项选择题 The doctor's ______ is that she'll soon be as good as new if she takes insulin and watches her diet.

单项选择题 We listened dumb-struck, full of ______ to the shocking details of the corruption of the ex-president of the company.

单项选择题 Hydrocarbons, ______ by engine exhausts, react with nitrogen oxides in the presence of sunlight to form complex toxic gases.