Never look a gift horse in the mouth lest you be accused of being ungrateful.
Students need to be taught to observe rules and regulations on campus.
Private citizen is one who does not hold an official or public position.
"Heads up" is a warning or alert given in advance on something you don't know of.
"In the same league" means sharing the same qualities others have.
Chinese tourism workers need to change their concept of tourism.
Due diligence means the proper effort and care one is obligated to pay.
So, is it okay to revive the boat tracker as a cultural relic?