He began to __________ because every means _______ tried already.
The stars who advertise some false medicine _____ for the deaths caused by the medicine.
The pilot asked all the passengers on board to remain________ as the plane was making a landing.
______ a piece of ice outside in such hot weather, and you’ll soon find it melt.
______ it is to listen to music when you are free.
—What are you going to do this weekend?—_______. If time permits, I may go to Shanghai with my friends.