Direction: For this part you are allowed 30 minutes to write a composition on the topic :Cell Phones .You should write no less than 120 words and base your composition on the outline below:
1、描述上圖所示的手機用戶數的變化情況 2、出現(xiàn)這種情況的原因 3、對此現(xiàn)象作出評價
A.血凝抑制實驗B.臨床癥狀C.病毒分離D.發(fā)病季節(jié)