1. （如果参加）eco-travel and you will find it will help you understand the importance of nature.(take)
2. He was so angry with himself for ______________________（犯了个如此愚蠢的错误）. （so）.
3. Luckily, we brought a road map with us without which _____________________（我们就迷路了）.（get）
4. _____________________ (人们所忧虑的事)is weather the poisoned milk powder attracting public attention will be on the market continually. (concern)
