A:铁丝在空气中燃烧,火星四射
B:白磷在空气中燃烧,产生白烟
C:木炭在空气中燃烧,生成二氧化碳
D:硫粉在空气中燃烧,产生蓝紫色火焰
—Excuse me! You can't take photos here.Look at the sign. It says “NO PHOTOS”.
— Sorry,I _________ see it and I _______ do it.
将洋葱表皮细胞放入30%的蔗糖溶液中,细胞液的浓度及颜色变化是 ( )
选择合适的字母补全下列单词。
①g____rden
②fa____m
③shee____
④carr____t
⑤to____ato