已知丁基共有四种。则分子式为C5H10O的醛应有 [ ]
A.3种
B.4种
C.5种
D.6种
B
Where are you going this afternoon?[ ]
A. Next to the shoe store.
B. I'm going to the bookstore.
C. He is going to visit his grandparents.
在暂停期间,允许队员离开比赛场地和坐在球队席上。