The students were ____ over the ____ problem, listening to the teacher with a ____
expression on their faces.
| A．puzzled; puzzling; puzzling | B．puzzled; puzzling; puzzled |
| C．puzzling; puzzling; puzzled | D．puzzling; puzzled; puzzling |
It is easy for people to ________ the bad habits such as smoking and drinking, which are not so easy to get rid of.
| A．break into | B．look into |
| C．slide into | D．knock into |
She now has to return home to have a long-time rest at her young age, because her health _____ under the great pressure of work.
| A．broke away | B．broke up |
| C．broke down | D．broke off |
________ stopping polluting the earth ________ hope to live in a better environment.
| A．Only to; we can | B．Only to; can we |
| C．Only by; can we | D．Only by; we can |
His friends were ___________and encouraged him to publish his ideas, but Copernicus was cautious.
| A．technical | B．official |
| C．educated | D．enthusiastic |
Our school was ________ in 1925 and has a history of more than 80 years.
| A．set up | B．set off |
| C．set out | D．found |