You must be ___when you cross the street 可以是carefully吗？

You must be ___when you cross the street 可以是carefully吗？ You must be strong . you must be You must be hungry You must be joking You must be confident. You must be dreaming you must be careful you must take your turn when you buy the train ticketyou must ___ ____ ___when you buy the train ticket改同义句并说明一下理由 (D.)___when you cross the road.A.Do care B.Care C.To be care D.Do be carefull (D.)___when you cross the road.A.Do careB.CareC.To be careD.Do be carefull you must be ___!(kid) You must be carful next You must be happy oh., you must be joking,救命 You Must Be Strong 歌词 You must certainly be happy i must be cull you you must be mistaken是什么意思?