Kelly cooked dinner           her parents while they were cleaning the yard. 

A. with

B. for

C. to

斜坡型牙槽嵴的舌杆应安放在（）

A.牙槽嵴的非倒凹区

B.与黏膜轻轻接触

C.离开黏膜0.5mm

D.位于牙龈与舌系带之间不影响舌运动

E.牙槽嵴的倒凹区内