——Did you __________ much time watching Li Na's match last night?——Yes. It __________ me a few hours to watch this match.
A:spend; spent
B:spend; took
C: take; took
D:take; cost
小芳同学用如图所示的实验装置探究“水沸腾时温度变化的特点”.
CrO3主要用于电镀工业,做自行车、仪表等日用五金电镀铬的原料.CrO3具有强氧化性,热稳定性较差,加热时逐步分解,其固体残留率随温度的变化如图1所示.
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