Tom took a taxi to the airport, only _______ his plane high up in the sky.
| A．finding | B．to find | C．being found | D．to have found |
—Have you heard about the recent election?
—Sure, it _______ the only thing on the news over the last three days.
| A．would be | B．is | C．has been | D．had been |
Don’t treat the vase as if it _______ made of steel.
| A．is | B．was | C．were | D．had been |
Although we met with some difficulties in building the railway, we were still _____ about finishing it before the deadline.
| A．consistent | B．enthusiastic | C．responsible | D．optimistic |
There are some health problems that, when _____ in time, can become bigger ones later on.
| A．not treated | B．not being treated | C．not to be treated | D．not having been treated |