用所给动词的正确形式填空。
I____(not know) him two years ago.
When it is fine tomorrow, we____ (go) to the park.
Peter____ (not go) to school yesterday because he ____(be) ill.
When Linda ____ (be) young, she danced very well.
读下图,分析回答下题。如果此图为热力环流侧视图,则以下说法正确的是( )
2015年10月5H,屠呦呦因为发现青蒿素成为首位获自然科学类诺贝尔奖的中国人.青蒿素受热易失去活性,为了从溶液中提取青蒿素,她创造性地选用乙醚代替水或酒精,这是利用乙醚具有( )