It was a great _____ for him to be pleasant to people he didn't like.
| A．attempt | B．trouble | C．power | D．effort |
After his journey from Beijing during the National Day, Tom returned school, __________.
| A．exhausting | B．exhausted | C．being exhausted | D．having exhausted |
---The light was on all night long.
---Yes. It seemed that Mike ________. He was the last one to leave the office.
| A．was to be blamed | B．was to blame |
| C．had been blamed | D．should be blamed |
He became inspired when he thought about helping ordinary people _________to cholera.
| A．expose | B．exposing | C．to expose | D．exposed |
At first, my new surroundings were difficult _________
| A．to be tolerated | B．tolerating | C．to tolerate | D．being tolerated |
There is a system ________the waste is disposed of using the principles of ecology.
| A．which | B．where | C．that | D．at which |