30. Only those who have experienced hardship ____ well aware of what happiness means.
| A．can they be | B．they can be | C．can be | D．they can |
Although it has been buried underground for over 1,000 years, the ancient queen's body remains well ________.
| A．defended | B．preserved | C．guarded | D．organized |
Scientists are convinced _________ the positive effect of laughter ________ physical and mental health.
| A．of; at | B．by; in |
| C．of; on | D．on ; at |
The old painter is perfectly __________ to live in a hut and paints pictures all day.
| A．likely | B．fit | C．content | D．curious |
It was the boy, rather than his teacher, that ____ for what he had done.
| A．were to blame | B．were to blamed |
| C．was to blame | D．was to be blamed |
He found a lot of ________ were ________.
| A．passers-by；grown-ups | B．passer-bys；growns-up |
| C．passer-bys；grown-ups | D．passers-by；growns-up |