With his eyes ________ the work attentively, he didn’t know what was happening outside.
Jack could have avoided that terrible car accident, but he ________ careful enough.
The climate change conference has come to __________ end, but the developing countries are dissatisfied with __________ small step that the developed countries have taken to reduce the emission(排放) of water gases.
--Don’t smoke any more, Ralph ! It is very bad for your health ! --I know I should give up smoking, but ________.
He glances briefly towards her but there is no sign of ________. After all, it’s 15 years since they last met.
In the rush hour, hiring ________ taxi for you to do what you are eager to do may be ________ better choice in our city.