To select the appropriate word to complete the sentence, we need to consider the context and grammar rules involved:
The contractor did not keep his promise that the work ........ be finished before the end of the week.
Here, the sentence talks about a promise related to a past action. In this context, the correct tense to use in the subordinate clause is the past form of the future tense "will," which is "would."
- Shall: This word is generally used to express the future tense or to make suggestions/promises. It does not fit well here since the sentence does not suggest a formality or a suggestion.
- Could: This word expresses possibility or ability in the past. The sentence focuses on a promise, not on the ability or possibility, so it is not suitable.
- Would (Correct Choice): This word is used to express a future action from a past perspective. The sentence structure "did not keep his promise that the work would be finished" correctly indicates that the work was supposed to be completed in the future as per a previous plan or promise.
- May: This word expresses probability or permission in the present or future. It is incorrect in this context, as the sentence is in the past tense.
Conclusion: The correct word to complete the sentence is "would," as it appropriately indicates the expectation of future completion from a past perspective.