蘑菇和霉菌的共同特征不包括（ ）

用化学方程式表示：(1)暗紫色固体A分解____

②将细铁丝放在D中点燃的化学方程式____

How do we know the weather? We learn it on the radio and TV every day. Different countries have different weather. For example, the weather in Australia is different from that in China. Because the seasons in Australia are the opposite. Its summer is from December to February. But in our country, it's winter this time. And its winter is in June, July and August. So when it's spring in China, it's autumn in Australia. Isn't it interesting?

已知a是锐角，求证：cos（sina）＞sin（cosa）．

家里某用电器发生短路，熔丝立即熔断，用下列方法进行检测，如图所示，断开所有用电器的开关，用一个普通的白炽灯L作为“校验灯”，与熔断的熔丝并联，然后只闭合S、S₁，若L正常发光，说明L₁____；只闭合S、S₂，若L发出暗红色的光(发光不正常)，说明L₂____。(填“正常”、“短路”或“断路”)。通常人体安全电压____，生活中要注意用电安全。