An ecosystem consists of the living and nonliving things in an area __________ interact(互相作用) with one another.
___ is believed ___ more and more people would fly to the moon in the future.
This ____ of trousers ____ fit me. Please show me ____.
She likes to use words ___ is clear to us.
He got home from work only to find the door ___ and something ____.
In our class everybody regards ___ difficulties as his own.