The world Expo 2010 is being held at a time ( )the world is looking for a new kind of balance between nature and cities
A when
B where
C which
D that
where did you see him for the first time ?
It was in the factory ( )we worked
A that
B where
C which
D when
China’s new food law provides for a food recall system ( )producers have to stop production if their food isn’t up to standard
Awhere
Bthat
Cwhen
Dwhich