__________ warm at night, I would fill the woodstove, and then set my alarm clock for midnight so I could refill it.
| A．Staying | B．Stayed |
| C．To stay | D．Stay |
She ____________ the path as the trees around her became thicker.
| A．lost sight of | B．caught sight of | C．lost sight | D．caught sight |
Once ________ more attention, the little trees could have grown better.
| A．given | B．to give | C．giving | D．having given |
After ten hours’ operation, the doctors managed to _____the one-year-old twins at the head.
| A．isolate | B．separate | C．divide | D．remove |
It remains______ whether the medicine has side effect.
| A．seeing | B．to see | C．seen | D．to be seen |
New reports say peace talks between the two countries have ____with no agreement reached.
| A．broken down | B．broken out | C．broken in | D．broken up |