His lips curved in a barely perceptible smile.他的嘴角弯了弯,露出一丝几乎察觉不到的笑容.a perceptible drop in temperature可以觉得出气温下降了a clearly perceptible decline in public confidence可清楚感觉到的公众信心的下降perceptible anger in his voice听他声音可以觉得出他发怒了Th...
In the reaction of acetylation and nitration 1,2 ? dichloroethane was used as solvent.在乙酰化、硝化反应中引入了1,2-二氯乙烷溶剂.Polyurethane demulsifier for crude oil were prepared from polypropylene glycol, xylene, toluenediiso - cyanate...