Mr. Brown is _____ a teacher to us; we look on him as our friend.

Always remember to put such dangerous things as knives out of children’s ________.                                                                     (2011·四川，13)

(2013·台州高三检测)Linda’s health is improving________day by day，and the doctor has advised her to stay home for a couple of weeks.

To protect the environment, the local government has put up a lot of ______ to warn the citizens not to litter the ground.

As the report said, the shopping center was a ________ failure and soon closed.