阅读下面短文，在文中空白处填入最适当的词语，使文章完整。（每空限填一词。）

Dear Toby,

Your trip sounds exciting! I can’t wait to hear ___小题1:___ Africa is like.

Since my last letter to you, I have had a little adventure of my own. Early this morning, my mother and I took ____小题2:___ flight to Dunhuang, in the north-west of China. The desert out there was really quite amazing—I had never seen ___小题3:____ much sand in my life! While we were there, we arranged with a tour company to ride camels. I was really excited because this was the first time I had seen____小题4:___ up close. We had hoped that we could see some other wildlife on our trip, ___小题5:____ sadly we didn’t.

Since you are going to the Sahara, I have some advice—be sure to bring a large hat and a shirt with long sleeves—you’ll need these ____小题6:___ protection. The sun can be so brilliant that you’ll need to keep covered, ___小题7:____ you’ll get burnt—my cheek were red for days after my trip. And another thing, you’ll need to keep a good supply of water with you, since it is so dry and hot.

Looking forward ___小题8:____ receiving your postcards!

Best wishes

Aihua

分析陨石中的有机化合物的成分，可以知道宇宙中是存在生命前期物质的。