"What are the things that we can't take through the security check?"
I said 我们什么不可以带进安全检查, and got it marked wrong. Is it possible? Even I agree it sounds awkward, but it's one of those exercises where I was given the individual 字 and I had to put them together, and there was no 是，的，or 东西 available, which would have made it easier. (我们不可以带进安全检查的东西是什么? is what I would have liked to say).