配制好的流动相应通过适宜的0.45μm(或 0.22μm)滤膜滤过,以除去杂质微粒。
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Listen to the passage twice and fill in the blanks with what you hear.The main difference between Chinese and Western eating habits is that in the West everyone has their own plate of food, while in China the dishes are placed on the table and everyone shares. If you are being treated by a Chinese host, he will _____1_____ to give you a taste of many different types of dishes. The Chinese ________2________ their food culture, and will do their best to show their hospitality.The meal usually begins with ____3____ at least four cold dishes, to be followed by the main courses of hot meat and vegetable dishes. Soup then ______4______ followed by staple food ranging from rice, noodles to dumplings.Perhaps one of the things that surprises a Western visitor most is that some Chinese hosts like to put food onto the plates of their guests. This is a sign of __________5___________. It is always polite to eat the food. If you do not like it, just leave the food on the plate.
Experimental scientists conduct their research largely on _________ __________ and statistical calculations, which is called quantitative research.
Social scientists often gain their findings from written reports that are rich in __________ details but with _____________ mathematical calculations, which is called qualitative research.
In an quantitative research scientists design and perfom rigorous experiments under ________ conditions.