he was boiling drinking water over an open fire 这句话中的短语这里面的over an open fire是“在...上面”的意思?他和on 有什么区别?

He was boiling water over an open fire yesterday.翻译 when he was boiling drinking water over an open the emperor Shen Nong discovered tea when he was boiling drinking water over fire 翻译 Tom stoped （drink）some water because he was thirsty Mr.Green often__(drink) a lot when he was young. Finally,the water was boiling.(改为同义句） _____,the water was boiling. He was boiling drinking water over an open fire.fire作火的时候不是不可数吗为什么前边有an? My teacher gave us a suggestion that we-----drink water that isn't ----any more.A,not boiled B,not to,boiling C not ,boiling D,not to,boiledNOt only i but also David and Irais-----fond of playing basketballA ,an B,is C,are D,was------your test paper 关于过去式He is boiling some eggs,He boiled some yesterday.一、这是书上的一个例子,为什么变了过去式后不加was?二、如果he is boiling some eggs,完全改成过去式是不是就是he was boiled some eggs yesterday,三、 可以这样改句子吗3 When he arrived I was working in the garden.4 When he arrived I was typing letters.5 When he arrived I was shaving.6 When he arrived I was boiling the milk.7 When he arrived I was phoning to my sister.8 When he arrived I was People must drink ( ) water.A.boiled B.boil C.boiling D.to boil if you have a fever,you'd better drink more_____water .A.boiled B.boiling _______water is healthy for men to drink.A.boiled B.boiling C.boil D.boils Don't drink water that is not boiling这句话哪里有错 he was seen to drink.这个句子对吗? he was seen drinking.呢?he was seen drinking in / at a restaurant.应该用哪一个冠词呢?谢谢大家 he likes drink tea There was food,drink,bedding and camping equipment,of which he made good use.翻译 一个句子~WHEN和WHILE得转换Shen None discovered tea when he was boiling the drinking water over an open fire.这里面得WHEN能不能换成WHILE～为什么?