What do you do on weekends? Some people like to stay at home, but others like to leave home and do other things. My friend, Tom works hard in a factory. He has a son and a daughter.

    On weekends, he usually does the same things. On Saturdays he washes his car and clothes. On Sundays, he goes to a farm with his family by car. His parents live there. The farm isn't very big, but there're often many things to do on the farm. The children help feed (饲养) the animals. There are many animals on the farm. You can see sheep, cows, horses and pigs. Tom and his wife help in the fields. At the end of the day, children are very tired and hungry. Tom's mother gives them a big meal. They are very happy.

尽管双目失明，双耳失聪，她仍然凭借顽强的拼搏和不屈的意志考入了哈佛大学，她就是(    )。

在菱形ABCD中，对角线AC=4，E为CD的中点，则$\overrightarrow{AE}·\overrightarrow{AC}=$____