One day an American called Simon went to London to visit his friend, Rick. Rick told him that his flat was on the first floor. When he arrived, Simon went straight to the first floor of the building. But he was told that there was no Rick on that floor. Do you know why?

    In fact, the British call the first floor of a building the ground floor. The floor above the ground floor is the first floor, while Americans would call it the second floor.

    The story shows that there are a few culture differences between Britain and America, though the British and Americans both speak English.

    The British usually hide their feelings. They seldom start a conversation with strangers. For example, on the train the British often spend their time reading newspapers or books. But Americans are quite different. They're more active and easier to talk with.

    The British and Americans may use different terms for many things. The British usually use “football”, “eraser” and “mail” while Americans prefer to use “soccer”, “rubber” and “post”.

我国公民在法律面前一律平等，是指公民平等地（    ）

①享有权利            ②履行义务           ③制定法律           ④适用法律

张老师上课时做了趣味实验：他选择了一种指示剂（无色酚酞试液或紫色石蕊试液）、稀盐酸、稀NaOH溶液。他先用玻璃棒蘸取某种指示剂在白纸上写上“化学”，可是学生什么也看不见。然后用某种物质喷洒在白纸上，出现了红色的“化学”二字。接着，又向纸上喷洒另一种物质，红字消失。则他选用的指示剂是____，先喷洒的物质是____，后喷洒的物质为____。如果选用另一种指示剂情况会____.