Do you want to be healthy and thin? All of us will say: of course! But how to be healthy and thin? If you want to lose weight and keep healthy, the first way is to be on a diet. Eating too much is bad for your health and you will easily turn fat! The best way is to eat a little sugar, but more vegetables! The other way is to do more exercise! Sport is good for your health. You should keep running or walking for about twenty minutes every day. This is the most straightforward method. If you keep doing this for a long time, you will be more healthy.

(词汇提示：1) lose weight 减肥  2） be on a diet 按规定进食；节食  3）a little 少量的 
4）method方法  5）the most straightforward method最直接的方法)

“神舟五号”的成功发射与回收，表明我国的载人航天技术已经进入世界领先水平。在飞船的火箭推进器中常装有液态肼（用X表示）和过氧化氢（H₂O₂），它们混合时的反应方程式为：2H₂O₂＋X＝N₂↑＋4H₂O，则肼（X）的化学式为（    ）

We want two good            for our school show.

结合如图，黄河凌汛（受纬度位置影响，初春时节，上游河段开冻较早，河水挟冰块而下，水势汹涌，往往导致水位猛涨）形成的河段可能是（ ）