点燃火柴需要摩擦。

Lighting a match requires ___friction.

家庭成员之间的摩擦让晚餐变得很尴尬。

The ___friction between family members made dinner very awkward.

冰面上的摩擦力很小，所以很难急刹车。

There is very little ___friction on the ice, making it hard to stop quickly.