【正文】
Uturn turn around掉頭 You mustn39。t can mustn39。 mustn39。 cross the street when the light is red. help your mother do some housework. read in bed. learn English from your friend. swim in the sea because it39。 must“必須”,在肯定句子通常表示說話人的主觀意識,或要求對方必須做某事;mustn39。 Now the light is can cross