东欧某城有一块石碑，上面刻有文字：“1914年6月28日，加夫里诺·普林西普在这里用他的子弹，表达了我国人民对暴虐的反抗和对自由的向往。”碑文记载的事件是第一次世界大战的导火线。这个事件是(     )

卖炭翁

卖炭翁，伐薪烧炭南山中。满面尘灰烟火色，两鬓苍苍十指黑。

卖炭得钱何所营？身上衣裳口中食。可怜身上衣正单，心忧炭贱愿天寒。

夜来城外一尺雪，晓驾炭车辗冰辙。牛困人饥日已高，市南门外泥中歇。

翩翩两骑来是谁？黄衣使者白衫儿。手把文书口称敕，回车叱牛牵向北。

一车炭，千余斤，宫使驱将惜不得。半匹红绡一丈绫，系向牛头充炭直。

下表为某同学探究“光对鼠妇生活的影响”实验的初步设想，其中存在不合理之处，下列改进建议正确的是（  ）

    Calabash brothers（葫芦兄弟） are seven brave brothers. They live in Calabash mountain. They wear different clothes. The red calabash is strong, but he does not have his own ideas. The orange calabash has two bright eyes and ears. He can see far and hear clearly. The yellow calabash has a hard head. The green calabash can swim. The cyanine（青色的） calabash is good at fire and the blue calabash hides himself very well. The purple calabash has a magic gourd（葫芦）.

    One day a pangolin（穿山甲） breaks the cave and two monsters come out. They are Monster Scorpion（蝎子精） and Monster Snake（蛇精）. The seven brothers must fight with them and save the world.