176. These goods are t_________ to Japan by water not by land.

175. A s________ line is the shortest distance between two points.

174. In order to protect our environment, we mustn’t t______ away so much waste.

173. It was George Washington who led Americans to s______ for building an independent country.

172. The American t_______ in Iraq were reported to have a fierce fighting with the terrorists.

171. You should learn to speak in a friendlier s_______.

170. Three-quarters of the world’s s_______ is covered by water.

　　　　　　　　　　　　 Part 18: (page 171---180)

169. The twin brothers look very s______. I can’t tell one from the other.

168.---How do you think about his explanation?

---I don’t think it makes s_______.

167. All of a s_______, the ship hit an iceberg and came to a stop.