$\frac{4}{5}-(\frac{4}{5}-\frac{4}{5})=$ ____

A.They're under the bed.

B.It's my father's.

C.Try this.

D.I'm eleven.

E.So beautiful!

(____)⑴How old are you?            

(____)⑵Where are my trousers?     

(____)⑶The hat is so big.            

(____)⑷Whose jacket is it?          

(____)⑸Look at my dress.           

著名的赵州桥建于（   ）

将基因型为AaBb的植株的花药离体培养成幼苗，再用秋水仙素处理，使其成为二倍体，这些幼苗长成后的自交后代