Color-blind people often find it difficult to _____ between blue and green.
Maureen hasn’t been feeling well ________. You’d better go and see her.
As the president’s car appeared, the waiting crowds ______ loud cheers.
After the new method is _______, a lot of money will be saved.
He went down into the cold water and after ________seemed a long time, he came out.
Who is ______ you want to send to the front?