It’s obvious that his ______ to the problem is wrong, so we’d better try another way to solve it.

It was in the United States that I made the _________ of Professor Jones.

We must keep on learning if we want to keep up with the     of the changing times.

Jack is not very decisive, and he always finds himself in a ________ as if he doesn’t know what he really wants to do．

When questioned by the police, Daniels denied all ______ of the events and refused to cooperate.