东汉、魏、晋时期，我国北方的游牧民族不断内迁。原来生活在西北的____和____，由西向东迁入陕西关中。分布在蒙古草原上的____和____，由北向南迁到山西一带；而____迁到辽宁、陕西及河套地区。

西晋灭亡后，从4世纪初到5世纪前期，北方各族统治者先后建立了许多政权，历史上把北方主要的15个政权，连同西南的____，总称为“____”。

____世纪后期，氐族苻氏建立的____逐渐强盛并统一了黄河流域，皇帝____任用汉人____为丞相，锐意改革，加强集权，招抚流民，兴办学校，提倡儒学，缓和了前秦境内胡汉之间的对立和矛盾。

    （I）It was a surprising announcement: SpaceX, a private company（私人公司）, said it would fly two people to the moon next year (2019). This has not been attempted since NASA's Apollo moon landings about 45 years ago. In the news conference, Elon Musk. SpaceX founder said two people have already paid SpaceX a “wonderful” amount of money to send them on a weeklong flight just beyond the moon.

    （II）Exercise reduces the risks of dying from all causes, including cancer and heart disease. But many people who work all week have little time for exercise. They try to take exercise or do chores to increase their heart rates over the weekend. A new study suggests that it is healthy to do that, which can reduce their risk of cancer and cardiovascular（心血管疾病）disease.

    （III）Scientists in London have found a possible way to solve the problem of plastic bottle waste. They have made a water bottle you can eat. The product is called Ooho, made of seaweed, a plant that grows in the ocean. Oohos are tasteless and look like bubbles or balls. They can hold water or any other liquid（液体）inside. When people drink Oohos, the outside bursts in the mouth and can be eaten. Even if you throw it away, it will degrade in about four weeks. It is good for the environment.

中央电视台《走遍中国》节目介绍了一种神奇果柑—黄果柑（下图），每年都会出现“花果同树”的自然奇观。黄果柑产地冬季气温日较差不大，平均气温在10℃左右，没有严寒，无霜期长。据此完成下面小题。