作家余秋雨曾经写道：“就在秦始皇下令修建长城的数十年前，四川成都平原上已经完成了一个了不起的工程……它至今还为无数民众输送涓涓清流。”下列历史人物中，主持修筑这个“了不起的工程”的是（  ）

设F₁、F₂是椭圆E：$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1(a>b>0)$的左、右焦点，P为直线$x=\frac{3}{2}a$上一点，△F₂PF₁是底角为30°的等腰三角形，则E的离心率为（  ）

根据短文理解，选择正确答案。

    We are all learning English, but how can we learn English well? A student can know a lot about English, but maybe(可能)he can't speak English.

    If you want to know how to swim, you must get into the river. And if you want to be a football player, you must play football. So, you see. You can learn English only by using it. You must listen to your teacher in class. You must read your lessons every day. You must speak English to your classmates and also you must write something sometimes. Then one day, you may find your English very good.

古诗词鉴赏。

虞美人  梳楼

宋蒋捷

丝丝杨柳丝丝雨，春在溟濛处。楼儿忒小不藏愁。几度和云飞去觅归舟。

天怜客子乡关远，借与花消遣。海棠红近绿栏杆。才卷朱帘却又晚风寒。

     【注释】①溟濛（míng méng）：形容烟雾弥漫，景色模糊。②忒（tuī）：太。