. It is on thing to accuse a person of a certain crime, but ________.
| A．to prove it is quite another matter | B．proving it is difficult |
| C．it is hard to prove | D．how to prove is difficult |
He is very popular among his students as he always tries to make them_____in his lectures.
| A．interested | B．interesting | C．interest | D．to interest |
Lucy’s new job paid twice as much as she had made______in the restaurant.
| A．working | B．work | C．to work | D．worked |
Ladies and gentlemen, please remain________until the plane has come to a complete stop.
| A．seated | B．seating | C．to seat | D．seat |
He told us whether_____a picnic was still under discussion.
| A．to have | B．having | C．have | D．had |
David threatened______his neighbour to the police if the damages were not paid.
| A．to be reported | B．reporting | C．to report | D．having reported |