如何使用 "must" 造句

1. Scientists studying combustion must rely on guesswork .
研究燃烧的科学家必须依靠猜测。
2. This is where leaders must play their roles .
管理者在其中必须发挥作用。
3. But you must really listen .
你要真正地倾听。
4. But he must do more .
但奥巴马要做得更多。
5. Must I go with you ?
要我和你一起去吗?