—Look, those great notebooks are _____ in our school store. Let's have a look.

—OK. Anybody can _____ the prices. [ ]

A. sell, buy            

B. sell, afford        

C. on sale, afford        

D. on sale, sell

早期妊娠的确诊依据是（ ）

A．停经史

B．早孕反应

C．尿妊娠试验

D．黑加征

E．B型超声检查