色谱-质谱联用(GC-MS)要解决的关键问题是如何将MS的真空度降低，以和GC的真空度相匹配。( )
联用技术是将两种或两种以上分析技术相联接，互相补充，从而完成复杂的分析任务。( )
According to Paragraph 5, when one is in the second stage of culture shock, one
A. is polite and gracious to foreigners
B. makes jokes about the host culture
C. finds the native people unsympathetic
D. enjoys the customs of the host culture
A．Give the secretary Janet"s new address and phone number.B．Ask Janet a question
A. Give the secretary Janet"s new address and phone number.
B. Ask Janet a question about his health.
C. Get information about Janet from the secretary.
D. Visit Janet at her new school.
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