体温调节中枢和体温感觉中枢分别在

    Jim is from New York(纽约). His home is near the school. So he often goes to school by bike. Every day it takes him about fifteen minutes to get there. He always gets to school on time(准时).

    Mary is a student of a middle school in Tokyo（东京）. The school is far from her home. Every day she has to go to school by subway. It takes her about forty minutes, she often gets up very early because she doesn't want to be late for school. She is a good student.

    Jenny's home is in London. It is far from her school. She usually goes to school by bus. This kind of bus has two floors. It takes her an hour every day. She must get up very early every morning. She often gets there early.

    Tom is a student of a middle school in Iceland（冰岛）. There is snow all year around. So he usually goes to school by sledge（雪橇）. It takes about twenty minutes to get there. He is sometimes late for school.

实验室可用如图所示装置进行多个实验探究，请回答下列问题．

（1）若液体A为稀盐酸，试管中发生反应的化学方程式是　 ____，反应现象是 ____．

（2）若液体A为蒸馏水，放置一段时间后试管中的现象是 ____

（3）若一段时间后，观察到浸没在液体A中的铁钉表面覆盖一层红色物质，则试管中发生反应的化学方程式可能是　 ____．