Martin enters into a verbal contract with Marlowe Ltd. to investigate their operations and their accounting systems, make recommendations as to how to improve them, and help implement the changes Marlowe Ltd accepts. In the negotiations, Martin makes it clear that he cannot give Marlowe Ltd. a definite timetable and that it is clear that the whole process will take longer than a year. Part of their agreement is that either party may terminate the contract on 60 days' written notice to the other if the work is progressing unsatisfactorily. The agreement that the arrangement can be terminated is an implied term of the contract. O a collateral agreement O a condition subsequent a condition precedent past performance