Another food crop raised by Indians ______ was strange to the European was called Indian corn.
. ___ is known to us all is that the 2010 World Expo will take place in Shanghai.
. We decided to turn to ___ can help us out.
. --- What do you think made Mary so upset? --- __ her new bicycle.
. They ___ out because the light’s on. Let’s go upstairs and have a look.
. I think ___ necessary ___ a foreign language.