A:铝粉投入到NaOH溶液中:2Al+2OH-===2AlO+H2↑
B:AlCl3溶液中加入足量的氨水:Al3++3OH-===Al(OH)3↓
C:三氯化铁溶液中加入铁粉:Fe3++Fe===2Fe2+
D:FeCl2溶液跟Cl2反应:2Fe2++Cl2===2Fe3++2Cl-
⑴把蜡烛B放到箱子侧面MN的右侧桌面上并点燃;
⑵移动蜡烛B,直到____;
⑶用刻度尺测出____的距离,就等于A到MN的距离.
在测量过程中,点燃蜡烛B是为了____ .
⑷为了便于观察,该实验最好在____环境中进行(填“较明亮”或“较黑暗”).
Do you has enough time?____
--- What do you think of the dress?--- Wonderful. I don't think I can find a ________ one.