请根据所给中文提示完成下列句子。 1. We should try our best to protect our __________ (环境) . 2. When you look up a word in the __________ (字典), pay attention to the first letter of the word. 3. I called you but __________ (没有人) answered the phone 4. We got much __________ (知识) of music from Mr.Lee last week. 5. Tony, you are always so ___________ (粗心的) .