Do be careful with that vase!

务必小心那个花瓶！

Do be careful not to mix the liquids!

小心，切勿将几种液体混起来！

So it must be slippery outside. Do be careful!

所以外面一定滑。一定要当心。

Do be careful . There are wolves in the mountain.

一定要小心。山上有狼。

Do be careful with those fireworks; the slightest spark could set them off.

烟火要格外小心， 稍有火星就能引起爆炸。