Nelson Mandela, former president of South Africa, devoted himself        to making the black and white equal.

The patient’s progress was encouraging as he could ______ get out of bed without help.

 His face looks brown because he works ____ all day.

Mr. Lin’s comments were very difficult to follow because they were ______related to the topic under discussion.

---Why do you pay a visit to your parents ________?---_______ they live in a remote village far from here.