When China's astronaut Zhai Zhigang carried out the spacewalk on September 27, he was wearing a spacesuit developed by Chinese scientists. Being worth more than 30 million yuan, the Feitian (飞天) spacesuit is not ____ordinary one.

    It ____（take）Chinese scientists four years to develop it. But what is special about the suit? First Let's take a look at why____（astronaut） need to wear spacesuits.

    When you visit a world with little or no atmosphere, not____(wear) a spacesuit, the following things would happen:

    You would become unconscious within 15 seconds because there is no oxygen.

    Your blood and body fluids(液体) would “boil” and then “freeze” ____ there is little or no air pressure.

    You would receive various types of radiation.

    You could____(hit) by dust or rock that moves at high speeds.

So, to protect you____these dangers, a spacesuit must:

    Have a pressurized atmosphere;

    Give you oxygen;

    Keep a(n) ____(comfort) temperature;

    Let you see clearly and move easily.

    The Feitian suit did all that and what it ____（do）made it like a mini-spaceship in____the astronaut stayed alive in outer space and carried out tasks.

我国年降水量地区分布的总趋势是（）

计算下列各式．