B细胞经抗免疫球蛋白荧光抗体染色后，其表面呈现的荧光随时间的变化规律是( )

A．环状—帽状—斑点状—消失

B．环状—斑点状—帽状—消失

C．斑点状—环状—帽状—消失

D．帽状—斑点状—环状—消失

E．斑点状—帽状—环状—消失

--- How soon will you start your journey?

--- I'm not sure.  I haven't decided_______.

A．when shall I ask the boss for leave

B．where I will go to spend the holiday

C．if I would go by train or by plane

D．who should I travel with