Anyone, whether he is an official or a bus driver, should be     respected.

(2009年合肥市高三第一次教学质量检测)The police tried to get some clues from the suspect，but he remained     ．

Nowadays, a lot of children have less time to play and communicate with their peer due to extra studies. ________, it is difficult to develop their character and social skills. 

Mr.Smith used to smoke __________ but he has given it up.

There is ____ nothing interesting in his speech.