自然威胁英文作文【一】
In last summer vacation ,I went to Beijing with my family. First ,we went to the Great Wall,where we met a lot of foreigners and we also took a lot of photos. They all like our culture and beautiful senery. Second.we went to the summer palace ,where the previous emporers spent summer in the old days.Third, we went to the Forbidden City .Finally ,we went to Wangfujing Street where we tasted much delicious food.
In a word, we had a great time during the vacation and we leanred a lot from this tour.
自然威胁英文作文【二】
输血传播：如果血液里有艾滋病病毒，输入此血者将会被感染。血液制品传播：有些病人（例如血友病）需要注射由血液中提取的某些成份制成的生物制品。如果该制品含有艾滋病病毒，该病人就可能被感染
