词汇运用

1. The          (丧失) of living areas is not good news for wolves.

2. These teachers often         (鼓励) their students to learn English well.

3. Many           (观光者) go to Zhalong to watch birds every year.

4. That story happened in the         (north) part of our country.

5. It’s          (necessary) for parents to give their children too much money.

6. The students know the         (important) of learning English.

7. The sun         (shine) brightly yesterday.

8. He is so         (care) that he made many mistakes in this paper.

9. I like many subjects,          (include) English, art, geography and PE.

10.         (provide) enough food and warm clothes for them is strongly needed.

为了迎接太空时代的到来，美国国会通过一项计划：在2050年前建造成太空升降机，就是把长绳的一端搁置在地球的卫星上，另一端系住升降机，放开绳，升降机能到达地球上，人坐在升降机里．科学家控制卫星上的电动机把升降机拉到卫星上．已知地球表面的重力加速度g=10m/s²，地球半径R=6400km，地球自转周期为24h．某宇航员在地球表面用体重计称得体重为800N，站在升降机中，某时刻当升降机以加速度a=10m/s²垂直地面上升，这时此人再一次用同一体重计称得视重为850N，忽略地球公转的影响，根据以上数据可以求出得物理量有（　　）

①如果把绳的一端搁置在同步卫星上，可知绳的长度至少有多长

②可以求出升降机此时距地面的高度

③可以求出升降机此时所受万有引力的大小

④可以求出宇航员的质量．

A．①②③

B．①②④

C．②③④

D．以上选项都不对