男婴，生后40d做健康检查，向其家长进行卫生宣教，应介绍由于小儿不会吞咽所分泌的全部唾液而发生的生理性流涎，其发生的时间大多为

A．生后1～2个月

B．生后3～4个月

C．生后5～6个月

D．生后7～8个月

E．生后9～10个月

一Do you like English?

—Yes, but I think it's _______ subject of all. [ ]

A. the difficult

B. the most difficult

C. more difficult

D. most difficult