Do you want to celebrate your birthday in space? It would be very different from what you might do on earth. 【小题1】 The candles could not be lit because astronauts cannot start a fire in the spaceship. 【小题2】 Voices are almost the only things that are not changed by being weightless, which means that everything has almost no weight in space.

Some astronauts feel sick for the first few days in space. Some feel as if they have a cold all the time. That’s because without gravity, the fluids (液体) in their bodies move towards their heads. Their faces look a little fatter. 【小题3】

And because gravity is not pressing on the spine (脊椎). The spine relaxes and stretches (舒展). 【小题4】 But when they come back on earth, they shrink (收缩) to their regular height.

Since nothing has weight, astronauts can lift heavy objects easily. 【小题5】 However, it is harder to stay still in space than to move around, so the astronauts always hold onto something or tie themselves to something.