题目内容
超声波的频率范围
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人耳是否能听到声音决定于
产房中有四个婴儿同时啼哭，如果每个婴儿啼哭声音的声强级均为50dB，则四个婴儿同时啼哭的声强级是____________________ dB。（计算结果保留两位有效数字）
Listen to the following sentences and fill in the blanks.(1)Without considerate____________________ and pricing decisions the e-shop owner may get into trouble.(2)Deciding which products to sell online can be quite a task and you need to take so many things into consideration such as _____________________, competition and profit.(3)Apparel and fashion, with its endless ________________ and relatively low shipping costs, is clearly a great category for new sellers to explore.(4)With your ____________________ you need to accommodate for competition dynamics, cultural factors, taste profiling, packing design, language, pricing and much more.(5)This e-commerce platform helps you purchase goods that are of great value and also offer an _______________________ .
使用万用表的电阻档测量线路的电阻,阻值为0时,代表线路( )
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