When ______ different cultures, we often pay attentiononly to the differences without noticing the many similarities.

Everyone knows thfrom playing with fire.

too much is bad for your health.

He is very popular among his students as he alwaystries to make them ____ in his lectures．

(2009年合肥市高三第一次教学质量检测)He sighed again and the failure in physics seemed to have completely his confidence．