29.　 Before she could move, she heard a loud noise, which grew to a terrible r____.

28.　 Jeff _____(拖曳) her towards the house.

27.　 She ____ (斗争)for her life, and finally pulled herself up.

26.　 The next moment the first wave swept her down, _____ (吞没)the garden.

25.　 Eco-travel is a form of travel that _____(结合)normal tourism with learning.

24.　 Wear a hat to p_____ yourself from the sun..

23.　 Watch out for dangers such as spiders, snakes or _______(有毒的)plants.

22.　 Hiking is fun and exciting, but you shouldn’t forget _______ (安全).

21.　 The basic e_________　 you need for hiking is simple : good shoes, clothes and a backpack.

20.　 You will get close to nature and take _____(运动) at the same time.