I think you should be careful about talking of the rebels as heroes.

我认为你还是当心点好，别把叛乱分子说成是英雄。

He really must be careful about thinking aloud. Who knew what he might say?

他真地得对自言自语小心点。谁知道他可能会说什么？

People should be careful about their possessions and not leave them lying around.

人们应该看管好自己的物品，不要到处乱放。

Be careful about which fonts you use because the wrong one makes you look like a proper wally.

选择字体时一定要细心，因为错误的字体会让你看起来像个真正的笨蛋。

Be careful about what you say.

对你所说的话小心点。