When his headaches developed Nick became bad-tempered and even violent.尼克出现头痛时脾气就变得很差，甚至还会动粗。Larry began suffering severe headaches and violent mood swings.拉里开始出现严重的头痛和剧烈的情绪波动。It is necessary initially to classify the he...
We must find economical methods for extracting oil from shale.我们必须找到从页岩中采油的经济方法.We can extract oil from shale.我们可以从页岩中提取石油.More ammonium sulphate solution is being recovered in the process of distilling oil shale.在提炼油页岩的...