石油组分
参考答案：
利用不同有机溶剂对石油的不同成分的选择性溶解进行某种程度和性质的分离，由此而作的各种组分的分类。
《轮机日志》在航行中，由（）负责填写并签字；停泊中，由值班人员负责填写并签字。
The major problem with E-mail is that it is (71) easy to use that people can become (72) with messages (73) they can possibly answer in a day. In addition, mail boxes require some management to (74) messages or archive those that might be required later. Senders don’t always know about your E-mail backlog and often send (75) messages.
A. fullB. lost C. inundated D. filled
