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1年前
如图所示,某同学在探究凸透镜成像规律的实验中,将焦距f =10cm的凸透镜固定在光具座上50cm处,将光屏向________
1年前
In order to protect the environment, people are greatly encouraged to travel by public ____. [ ]
1年前
“这一整天,谁也没买过她一根火柴,谁也没给过她一个硬币。”从三个“一”让你想到了什么?
1年前
Imagine the following scene: on the grasslands, an elephant stands under an umbrella-like tree.
1年前