皮皮学，免费搜题
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【判断题】
挥发油提取时可用溶剂萃取法,、石油醚( 30-60 °C)、二硫化碳、四氯化碳等有机溶剂采用回流浸出法或冷浸法进行浸提。此法得到的挥发油含脂溶性杂质较多,需将挥发油冷冻析晶进行纯化。A.
正确
B.
错误
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皮皮学刷刷变学霸
举一反三
【单选题】We want to be ______ because, as students, we should learn to help other people.
A.
performers
B.
interviewers
C.
patients
D.
volunteers
【单选题】What is the message mainly expressed in the story?
A.
We should learn to be generous.
B.
It is honorable to help those in need.
C.
People in high positions are not like what we expect.
D.
We should avoid judging people by their appearances.
【单选题】Earth Day is set to remind people to ________ the world we live in and we should learn to respect life and nature. [ ]
A.
care for
B.
take care
C.
care about
D.
think of
【单选题】What is the inegge mainly expressed in the story?
A.
we should learn to he generous
B.
It is honorable to help those in need.
C.
People in high postans are not like what we expect
D.
We should avoid judging people by their appearances.
【简答题】We should learn to avoid (make) ______ the same mistake again.
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