There will not be enough space to the earth in the future.

Mary and Linda ________ good friends.

Some researchers believe that there is no doubt _______ a cure for AIDS will be found.

We ran down to the shore in time to see an enormousanimal opposite us _____itself out of the water and then _____ down again,which was a whale..

Some of my friends eat with their eyes. They prefer to order what _____ nice. What about you— I think it’s good to eat some fresh vegetables.