This is my home. Look, there are lots of things here. There are two black shoes. They are my mother's. Look at the bed, there are two shirts. They are white and they are my father's. There are many toys in the boxes. They are w
1千米=____米,km表示____
诗句填空。①学而不思则罔, 。② ,便引诗情到碧霄。③最是一年春好处, 。④ ,可以为师矣。⑤《西江月》中“ , ”两句,通过嗅觉和听觉来捕捉夏夜景物特征,给人印象鲜明而深刻。
某种细菌的直径是0.0000005厘米,用科学记数法表示为____厘米.
用图甲所示的装置测出凸透镜的焦距,并“探究凸透镜成像规律”,当蜡烛、透镜、光屏位置如图乙时,在光屏上可成清晰的像.下列说法正确的是 ( )