مولد صوت AI مجاني 9.19数理化 من Fish Audio

这班里边都有谁在做课前预习的，站起来。同学们看看，这些同学每次考试都是年级前二十。这班里边都有谁坚持做错题本的，站起来。看到了吧，这就是成绩提升的秘诀。

五年级数学有个坑，很多家长都没注意到。分数运算特别是约分，看似简单，实际上是很多孩子的拦路虎。不重视这一块，到了六年级会很吃亏，建议提前预习打基础。

Watch what happens when you place a penny in lemon juice overnight: the copper surface turns bright and shiny. Add baking soda to vinegar in a balloon, stretch it over a bottle, and the balloon inflates itself. These simple reactions demonstrate basic chemistry principles.

When you place a paper clip on water's surface it floats due to surface tension but add a drop of soap and it sinks instantly if you put dry ice in soapy water it creates mysterious fog bubbles that bounce and dance when touched these are simple scientific principles at work.

When you place a paper clip on water's surface, it floats due to surface tension, but add a drop of soap and it sinks instantly. If you put a metal spoon in hot water and touch it to a soap bubble, the bubble freezes in place like magic.

When you place a paper clip on water's surface, it floats due to surface tension, but add a drop of soap and it sinks instantly. If you wrap a dry paper towel in aluminum foil and put it in water, the towel stays completely dry.

When you place a paper clip on water's surface, it floats due to surface tension. Add a drop of soap, and it sinks instantly. Fill a glass with hot water, place it upside down on ice, and watch as the water vapor creates a miniature cloud inside.

When you place a paper clip on still water, it floats due to surface tension. Add a drop of dish soap, and it instantly sinks. Pour milk into a plate, add food coloring, then touch it with a soap-dipped toothpick - watch as the colors dance and swirl.