根据句意和汉语注释，写出单词的正确形式。

小题1:After the exam, our teacher came into the classroom with a        （满意的）smile on his face.

小题2:The little boy was thirty, so the old lady          （提供）him a glass of water.

小题3:For your own          （安全）, remember not to drive after drinking.

小题4:What a pretty gold ring! It was          （专门地）designed for her.

水中总大肠菌群系以100ml水样中所污染的总大肠菌群的[最大可能数（）表示。