This new kind of chemicals will help keep the air, soil and water________ from pollution.
| A．free | B．empty | C．loose | D．short |
She brought with her three friends，none of ________ I had ever met before.
| A．them | B．who | C．whom | D．these |
The house ________ I grew up has been taken down and replaced by an office building.
| A．in it | B．in | C．in that | D．in which |
I was born in New Orleans，Louisiana，a city ________ name will create a picture of beautiful trees and green grass in our mind.
| A．which | B．of which | C．that | D．whose |
It's helpful to put children in a situation ________ they can see themselves differently.
| A．that D | B．when | C．which | D．where |
—What do you think of teacher，Bob?
—I find it fun and challenging.It is a job ________ you are doing something serious but interesting.
| A．where | B．which | C．when | D．that |