【单选题】It seems that he is ______ and nobody can calm him down.
【简答题】(1)下面是教材下册中“物质溶解时的吸热或放热现象”的活动与探究。请你一同完成该探究并回答有关问题: 水中加入的溶质 NaCl固体 NH 4 NO 3 固体 NaOH固体 加溶质前水的温度/℃ 20 20 20 溶解现象 全部溶解 全部溶解 全部溶解 溶质溶解后溶液的温度变化 温度无明显变化 温度降低 温度升高 结论(“放热”或“吸热”) 固体氯化钠溶于水无明显放热和吸热现象 ① ② ③根据物质溶...
【单选题】以下几个跨境电商平台上的产品标题,哪个比较好?
A.
New Arrival Baby Dresses Dress for Girl Kids Clothes Girl Dress Girls Clothes Kids Brand Printed Flower Dress
B.
Girl Jean Dress Children Clothes Summer Dresses for Girls Embroidery Cotton Clothing Girl Princess Rabbit Dress
C.
2019 New Arrival 100% Cotton Girl Party Dress Flowers and Butterflies Girl Princess Dress for Weddings
【简答题】To us it seems that so natural to put up an umbrella to keep the water off the rains. But actually the umbrella was not invented as protection against rain. Its first use was as a shade against the su...
【简答题】写出下列反应的化学方程式,并完成题内填空. (1)写出加热碱式碳酸铜的化学方程式______.反应类型是______.生成物均属于______(选填“酸、碱、盐、氧化物”中一种). (2)将一枚生锈的铁钉(铁锈的主要成分是三氧化二铁),投入适量的稀硫酸中,溶液的颜色由无色变为______色,观察一段时间发现铁钉表面有气泡冒出,请写出上述反应的化学方程式______. (3)镁在空气中燃烧时,发出耀...
【简答题】二、完成下列反应方程式 1. 2. 3. 4. 5. 6.
【简答题】One day the famous American scientist Albert Einstein(著名的美国科学家爱因斯坦) came across(碰到) an old friend of his in a street in New York. “Mr Einstein” said the friend “ It seems that you need to have a new o...