单项选择题
I know it is difficult ______ him to talk like the lecturer, but I think he should grasp every chance.
单项选择题 In China children, even in their twenties depended ______ their parents ______ food and clothing.
单项选择题 It’s getting cold，Be careful （）your health.
单项选择题 They found the boy crying ______ the corner of the street.
