请问 in amounts of ca 5 percent是什么意思?? 这断话是 Without catalyst at a temperature of 80℃,the formation of 1,1-dichloroethylene was almost nil and of that formed,vinylchloride was present as an impurity in the distillate (in amounts of ca 5 percent) 括号里的翻译不出来,请大家帮帮忙 [ ]查看更多4个回答 . 2人已关注