地衣是哪两种生物的共生体（　　）

在Rt△ABC中，∠C=90°，a、b、c分别是∠A、∠B、∠C的对边，下列等式中正确的是（　　）

    My name is Bob.Tomorrow is Saturday.We have no classes.My parents aren't going to work，but we are going to be very busy tomorrow.My mother is going to buy something.My father is going to visit my aunt and uncle.I'm going to the bookstore by bus.Then I'm going to buy a dictionary.Tomorrow evening we are going to visit my grandparents and have a big dinner.After that we are going to the cinema.

—F____ It's the second（第二）month of a year.