While crossing the street, __________.
A: the light might be green
B: there are no policemen
C: be careful
D: it is necessary to be careful
A: the light might be green
B: there are no policemen
C: be careful
D: it is necessary to be careful
举一反三
- ______be careful when crossing the street! A: Must B: Should C: Ought to D: Do
- Be ______(care)while crossing the roads and remember to look left in Britain. A: careful B: careless C: caring
- Be careful when you ________ the street. A: are crossing B: is crossing C: crossing D: is cross
- Be careful when ______ the road. A: [A] crossing B: to cross C: cross
- You can never be _________ careful when crossing this busy road.