对此有机物CH₃CH=CHCH₃命名正确的是（　　）

A．2-丁烯

B．1-丁烯

C．2-甲基-1-丙烯

D．1-戊烯

I went to the beach and got plenty of rest.（） You looked tired last time I saw you.

A.I hope so 

B.Really

C.I'm glad you did 

D.The sound was nice