根据句意和中文意思，写出单词的正确形式。
1. The red lines on the map often _____(代表) railways．
2. Planting trees can help to make our _____(环境) clearer and more beautiful.
3. Sometimes it’s difficult for us to make _____ alone.(决定)
4. Seven _____of the trees have been watered so far.(二十)
5. He likes to wear yellow coats, because yellow is the colour of _____. (智慧)
