문제 내용: 밑줄 친 부분이 어법상 옳지 않은 것은?
선택지 1: You must plan not to spend too much on the project.
선택지 2: My dog disappeared last month and hasn't been seen since.
선택지 3: I'm sad that the people who daughter I look after are moving away.
선택지 4: I bought a book on my trip, and it was twice as expensive as it was at home.