—Becareful,children!You

問題詳情：

—Be careful, children! You ________ step on the grass.

—Sorry. We ________ do that again.

       A. needn’t; won’t        B. mustn’t; won’t       C. can’t; will   D. don’t have to; will

【回答】

B

知識點：虛擬語氣與情態動詞

題型：選擇題