五、首字母填空
In the future, people may travel to Mars by water-powered spacecraft! Today's spacecraft are fine for getting things into space, but they are not so good at travelling long (1) . These spacecraft burn chemical fuels (燃料) and they are very expensive. Scientists say that a water-powered spacecraft could make the trip to Mars much (2) . The idea is just in the planning stages now, but scientists think such a spacecraft could be (3) soon.
The key to the water-powered spacecraft is the engine (发动机). Regular engines push spacecraft by (4) fuel. The water engine will use steam created by solar panels (太阳能板) that heat water to a high (5) . Of course, the spacecraft will have to carry a lot of water for the long (6) to Mars. Today's spacecraft could not carry that much water. But scientists think that a spacecraft blown up like a balloon would be able to.
"Balloon" spacecraft could be very (7) and carry enough water for a long trip. With the "Balloon" spacecraft, enough water could be carried to power the engines and grow food during the trip. And the people on the spacecraft might even get to take a hot (8) !
Scientists say the biggest (9) of such a spacecraft would be the cost. The "Balloon" spacecraft uses water to push it through space and costs about one-thirtieth of a normal spacecraft. Such savings naturally encourage continued (10) into balloon spacecraft and water engines. If these scientists are correct, we may soon be on our way to Mars in a spacecraft powered by water.

1. distance 2. cheaper 3. designed 4. burning 5. temperature 6. journey 7. light 8. bath 9. advantage 10. research

1. 根据“travelling long”及首字母d，可知是“长途旅行”，填distance。
2. 由前文“expensive”及首字母c，可知水动力飞船更便宜，much后接比较级，填cheaper。
3. 结合“idea in planning stages”及首字母d，飞船将被设计，被动语态，填designed。
4. 常规发动机通过燃烧燃料推进，by后接动名词，填burning。
5. 太阳能板加热水到高温，“高温”为high temperature，填temperature。
6. “long”修饰去火星的旅程，填journey。
7. 气球状飞船能携带更多水，应是“轻的”，填light。
8. 携带足够水，可洗热水澡，“热水澡”为hot bath，填bath。
9. 下文讲成本低，是最大“优势”，填advantage。
10. 节省成本鼓励继续“研究”，填research。