Fill the gap with the most appropriate option from the list following the gap. One _____ be too careful these days; times are uncertain and walls have ears?

Fill the gap with the most appropriate option from the list following the gap.

One _____ be too careful these days; times are uncertain and walls have ears?

Answer Details

The most appropriate option to fill the gap is "can't". This means that one cannot be too careful these days because times are uncertain and walls have ears. The phrase "can't be too careful" is an idiom that means it is important to be cautious and vigilant in order to avoid trouble or danger. The speaker is emphasizing the importance of being careful and avoiding risks in the current situation.