Directions: The sentence has four underlined words or phrases. The four underlined parts of the sentence are marked (1), (2), (3) and (4). Identify the one underlined word or phrase that must be changed in order for the sentence to be correct.

After working (1) for one month on the project the students (2) are still left with some of the work which (3) have to be completed (4) before tomorrow afternoon. (5) No error