From the words lettered A to D below each of the following sentences, choose the word or group of words as it is used in the sentence He did all he could to...

Answer Details

The word that best completes the sentence and is used in the same way as it is in the sentence is "secure". This is because in the sentence, the person did everything possible to make the building stronger and more protected against attack. Therefore, the word that would fit this meaning is "secure" which means to make something safe and protected from danger.