In some languages, 100 words make up half of all words _______in daily conversations.

A．using

B．to use

C．having used

D．used

已知⊙O₁和⊙O₂的圆心距O₁ O₂=6cm，两圆的半径分别是2cm和4cm，则两圆的位置关系为（　　）

A．相离

B．外切

C．内切

D．相交