The rain comes from the_______. 

It is a pity that we have to ___________ the school trip because of the rainy days.

用元素符号或化学式填空：

（1）3个氮分子　 ____　

（2）4个硫离子　 ____

（3）n个铜原子　 ____　

（4）正五价的磷元素　 ____

阅读下面这首古诗，完成后面小题。
                                                                                                         冷香菊
                                                                                                         陈荣卿
                                                                                       晚秋风紧晓霜寒，香阵飘飘透竹帘。
                                                                                       荒径幽林甘冷落，肯于人世学趋炎？