临床上诊断HP感染最可靠的方法是（）

A.细菌培养

B.快速尿素酶试验

C.¹³C尿素呼气试验

D.¹⁴C尿素呼气试验

E.X线钡餐检查

—________that China has the largest number of iphone4s users now.

— I believe so.

A．Someone said

B．They told me

C．It is said

D．I was told to