上颌第一磨牙面的特征，正确的是（）

A.呈斜方形、远中舌尖最大、为主要功能尖

B.呈菱形、远中颊尖是最小的牙尖

C.远中颊尖与近中舌尖三角嵴相连构成斜嵴

D.远中舌尖与近中颊尖三角嵴相连构成斜嵴

E.近中舌尖与近中颊尖三角嵴相连构成横嵴

--- The two old friends were      busy      with each other      the time.

--- Yes. They haven’t met for long.         

A．too, to talk; to forget

B．too, talking; to forget

C．so, to talk; that they forgot

D．so, talking; that they forgot