In the bubble years, lending standards slipped ______,allowing   many people to put far too much of their income into paying for their housing.

We often say that something is “as light as air”, but air is＿＿＿light. 

The teacher told Tom to sit ______ in class.

The mother looked at the door _______，expecting the children’s coming．

This task is _____ for us. We need ______ people.